/*      $NetBSD: clock.c,v 1.60 2026/03/28 22:19:32 thorpej 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.
 *
 * 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 1.60 2026/03/28 22:19:32 thorpej Exp $");

#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/device.h>
#include <sys/systm.h>
#include <sys/timetc.h>
#include <machine/psl.h>
#include <machine/cpu.h>
#include <amiga/amiga/device.h>
#include <amiga/amiga/custom.h>
#include <amiga/amiga/cia.h>
#ifdef DRACO
#include <amiga/amiga/drcustom.h>
#include <m68k/include/asm_single.h>
#endif
#include <amiga/dev/rtc.h>
#include <amiga/dev/zbusvar.h>

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

/*
 * Machine-dependent clock routines.
 *
 * Startrtclock restarts the real-time clock, which provides
 * hardclock interrupts to kern_clock.c.
 *
 * Inittodr initializes the time of day hardware which provides
 * date functions.
 *
 * Resettodr restores the time of day hardware after a time change.
 *
 * A note on the real-time clock:
 * We actually load the clock with amiga_clk_interval-1 instead of amiga_clk_interval.
 * This is because the counter decrements to zero after N+1 enabled clock
 * periods where N is the value loaded into the counter.
 */

int clockmatch(device_t, cfdata_t, void *);
void clockattach(device_t, device_t, void *);
void cpu_initclocks(void);
static void calibrate_delay(device_t);

/* the clocks run at NTSC: 715.909kHz or PAL: 709.379kHz.
   We're using a 100 Hz clock. */
int amiga_clk_interval;
int eclockfreq;
struct CIA *clockcia;

static u_int clk_getcounter(struct timecounter *);

static struct timecounter clk_timecounter = {
        .tc_get_timecount = clk_getcounter,
        .tc_counter_mask = ~0u,
        .tc_quality = 100,
};

CFATTACH_DECL_NEW(clock, 0,
    clockmatch, clockattach, NULL, NULL);

int
clockmatch(device_t parent, cfdata_t cf, void *aux)
{
        if (matchname("clock", aux))
                return(1);
        return(0);
}

/*
 * Start the real-time clock.
 */
void
clockattach(device_t parent, device_t self, void *aux)
{
        const char *clockchip;
        unsigned short interval;
        int chipfreq;
#ifdef DRACO
        u_char dracorev;
#endif

        if (eclockfreq == 0)
                eclockfreq = 715909;    /* guess NTSC */

        chipfreq = eclockfreq;

#ifdef DRACO
        dracorev = is_draco();
        if (dracorev >= 4) {
                chipfreq = eclockfreq / 7;
                clockchip = "QuickLogic";
        } else if (dracorev) {
                clockcia = (struct CIA *)CIAAbase;
                clockchip = "CIA A";
        } else
#endif
        {
                clockcia = (struct CIA *)CIABbase;
                clockchip = "CIA B";
        }

        /* round nearest to mitigate clock drift for PAL */
        amiga_clk_interval = chipfreq / hz;
        if (chipfreq % hz >= hz / 2)
                amiga_clk_interval++;

        if (self != NULL) {     /* real autoconfig? */
                printf(": %s system hz %d hardware hz %d\n", clockchip, hz,
                    chipfreq);

                clk_timecounter.tc_name = clockchip;
                clk_timecounter.tc_frequency = chipfreq;
                tc_init(&clk_timecounter);
        }

#ifdef DRACO
        if (dracorev >= 4) {
                /*
                 * can't preload anything beforehand, timer is free_running;
                 * but need this for delay calibration.
                 */

                draco_ioct->io_timerlo = amiga_clk_interval & 0xff;
                draco_ioct->io_timerhi = amiga_clk_interval >> 8;

                calibrate_delay(self);

                return;
        }
#endif
        /*
         * stop timer A
         */
        clockcia->cra = clockcia->cra & 0xc0;
        clockcia->icr = 1 << 0;         /* disable timer A interrupt */
        interval = clockcia->icr;               /* and make sure it's clear */

        /*
         * load interval into registers.
         * the clocks run at NTSC: 715.909kHz or PAL: 709.379kHz
         */
        interval = amiga_clk_interval - 1;

        /*
         * order of setting is important !
         */
        clockcia->talo = interval & 0xff;
        clockcia->tahi = interval >> 8;
        /*
         * start timer A in continuous mode
         */
        clockcia->cra = (clockcia->cra & 0xc0) | 1;

        calibrate_delay(self);
}

void
cpu_initclocks(void)
{
#ifdef DRACO
        unsigned char dracorev;
        dracorev = is_draco();
        if (dracorev >= 4) {
                draco_ioct->io_timerlo = amiga_clk_interval & 0xFF;
                draco_ioct->io_timerhi = amiga_clk_interval >> 8;
                draco_ioct->io_timerrst = 0;    /* any value resets */
                single_inst_bset_b(draco_ioct->io_status2, DRSTAT2_TMRINTENA);

                return;
        }
#endif
        /*
         * enable interrupts for timer A
         */
        clockcia->icr = (1<<7) | (1<<0);

        /*
         * start timer A in continuous shot mode
         */
        clockcia->cra = (clockcia->cra & 0xc0) | 1;

        /*
         * and globally enable interrupts for ciab
         */
#ifdef DRACO
        if (dracorev)           /* we use cia a on DraCo */
                single_inst_bset_b(*draco_intena, DRIRQ_INT2);
        else
#endif
                custom.intena = INTF_SETCLR | INTF_EXTER;

}

void
setstatclockrate(int hertz)
{
}

/*
 * Returns ticks since last recorded clock "tick"
 * (i.e. clock interrupt).
 */
static u_int
clk_gettick(void)
{
        u_int interval;
        u_char hi, hi2, lo;

#ifdef DRACO
        if (is_draco() >= 4) {
                hi2 = draco_ioct->io_chiprev;   /* latch timer */
                hi = draco_ioct->io_timerhi;
                lo = draco_ioct->io_timerlo;
                interval = ((hi<<8) | lo);
                if (interval > amiga_clk_interval)      /* timer underflow */
                        interval = 65536 + amiga_clk_interval - interval;
                else
                        interval = amiga_clk_interval - interval;

        } else
#endif
        {
                hi  = clockcia->tahi;
                lo  = clockcia->talo;
                hi2 = clockcia->tahi;
                if (hi != hi2) {
                        lo = clockcia->talo;
                        hi = hi2;
                }

                interval = (amiga_clk_interval - 1) - ((hi<<8) | lo);

                /*
                 * should read ICR and if there's an int pending, adjust
                 * interval. However, since reading ICR clears the interrupt,
                 * we'd lose a hardclock int, and this is not tolerable.
                 */
        }

        return interval;
}

static u_int
clk_getcounter(struct timecounter *tc)
{
        static int prev_hardclock;
        static u_int prev_counter;
        int cur_hardclock;
        u_int counter;

        do {
                cur_hardclock = getticks();
                counter = clk_gettick();
        } while (cur_hardclock != getticks());

        /*
         * Handle the situation of a wrapped interval counter, while
         * the hardclock() interrupt was not yet executed to update
         * hardclock_ticks.
         */
        if (cur_hardclock < prev_hardclock)
                cur_hardclock = prev_hardclock;
        if (counter < prev_counter && cur_hardclock == prev_hardclock)
                cur_hardclock++;

        prev_hardclock = cur_hardclock;
        prev_counter = counter;

        return cur_hardclock * amiga_clk_interval + counter;
}

/*
 * Calibrate delay loop.
 * We use two iterations because we don't have enough bits to do a factor of
 * 8 with better than 1%.
 *
 * XXX Note that we MUST stay below 1 tick if using clk_gettick(), even for
 * underestimated values of delay_divisor.
 *
 * XXX the "ns" below is only correct for a shift of 10 bits, and even then
 * off by 2.4%
 */
__CTASSERT(DELAY_MAGSHIFT == 10);       /* XXX assumptions made here */
static void
calibrate_delay(device_t self)
{
        unsigned long t1, t2;

        if (self)
                printf("Calibrating delay loop... ");

        do {
                t1 = clk_gettick();
                delay(1024);
                t2 = clk_gettick();
        } while (t2 <= t1);
        t2 = ((t2 - t1) * 1000000) / (amiga_clk_interval * hz);
        delay_divisor = (delay_divisor * t2 + 1023) >> 10;
#ifdef DEBUG
        if (self)
                printf("\ndiff %ld us, new divisor %u/1024 us\n", t2,
                    delay_divisor);
        do {
                t1 = clk_gettick();
                delay(1024);
                t2 = clk_gettick();
        } while (t2 <= t1);
        t2 = ((t2 - t1) * 1000000) / (amiga_clk_interval * hz);
        delay_divisor = (delay_divisor * t2 + 1023) >> 10;
        if (self)
                printf("diff %ld us, new divisor %u/1024 us\n", t2,
                    delay_divisor);
#endif
        do {
                t1 = clk_gettick();
                delay(1024);
                t2 = clk_gettick();
        } while (t2 <= t1);
        t2 = ((t2 - t1) * 1000000) / (amiga_clk_interval * hz);
        delay_divisor = (delay_divisor * t2 + 1023) >> 10;
#ifdef DEBUG
        if (self)
                printf("diff %ld us, new divisor ", t2);
#endif
        if (self)
                printf("%u/1024 us\n", delay_divisor);
}

#if notyet

/* implement this later. I'd suggest using both timers in CIA-A, they're
   not yet used. */

#include "clock.h"
#if NCLOCK > 0
/*
 * /dev/clock: mappable high resolution timer.
 *
 * This code implements a 32-bit recycling counter (with a 4 usec period)
 * using timers 2 & 3 on the 6840 clock chip.  The counter can be mapped
 * RO into a user's address space to achieve low overhead (no system calls),
 * high-precision timing.
 *
 * Note that timer 3 is also used for the high precision profiling timer
 * (PROFTIMER code above).  Care should be taken when both uses are
 * configured as only a token effort is made to avoid conflicting use.
 */
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/ioctl.h>
#include <uvm/uvm_extern.h>
#include <amiga/amiga/clockioctl.h>
#include <sys/specdev.h>
#include <sys/vnode.h>
#include <sys/mman.h>

int clockon = 0;                /* non-zero if high-res timer enabled */
#ifdef PROFTIMER
int  profprocs = 0;             /* # of procs using profiling timer */
#endif
#ifdef DEBUG
int clockdebug = 0;
#endif

/*ARGSUSED*/
int
clockopen(dev_t dev, int flags)
{
#ifdef PROFTIMER
#ifdef PROF
        /*
         * Kernel profiling enabled, give up.
         */
        if (profiling)
                return(EBUSY);
#endif
        /*
         * If any user processes are profiling, give up.
         */
        if (profprocs)
                return(EBUSY);
#endif
        if (!clockon) {
                startclock();
                clockon++;
        }
        return(0);
}

/*ARGSUSED*/
int
clockclose(dev_t dev, int flags)
{
        (void) clockunmmap(dev, (void *)0, curproc);    /* XXX */
        stopclock();
        clockon = 0;
        return(0);
}

/*ARGSUSED*/
int
clockioctl(dev_t dev, u_long cmd, void *data, int flag, struct proc *p)
{
        int error = 0;

        switch (cmd) {

        case CLOCKMAP:
                error = clockmmap(dev, (void **)data, p);
                break;

        case CLOCKUNMAP:
                error = clockunmmap(dev, *(void **)data, p);
                break;

        case CLOCKGETRES:
                *(int *)data = CLK_RESOLUTION;
                break;

        default:
                error = EINVAL;
                break;
        }
        return(error);
}

/*ARGSUSED*/
void
clockmap(dev_t dev, int off, int prot)
{
        return MD_BTOP(off + (INTIOBASE+CLKBASE+CLKSR-1));
}

int
clockmmap(dev_t dev, void **addrp, struct proc *p)
{
        int error;
        struct vnode vn;
        struct specinfo si;
        int flags;

        flags = MAP_FILE|MAP_SHARED;
        if (*addrp)
                flags |= MAP_FIXED;
        else
                *addrp = (void *)0x1000000;     /* XXX */
        vn.v_type = VCHR;                       /* XXX */
        vn.v_specinfo = &si;                    /* XXX */
        vn.v_rdev = dev;                        /* XXX */
        error = vm_mmap(&p->p_vmspace->vm_map, (vm_offset_t *)addrp,
                        PAGE_SIZE, VM_PROT_ALL, flags, (void *)&vn, 0);
        return(error);
}

int
clockunmmap(dev_t dev, void *addr, struct proc *p)
{
        int rv;

        if (addr == 0)
                return(EINVAL);         /* XXX: how do we deal with this? */
        uvm_deallocate(p->p_vmspace->vm_map, (vm_offset_t)addr, PAGE_SIZE);
        return 0;
}

void
startclock(void)
{
        register struct clkreg *clk = (struct clkreg *)clkstd[0];

        clk->clk_msb2 = -1; clk->clk_lsb2 = -1;
        clk->clk_msb3 = -1; clk->clk_lsb3 = -1;

        clk->clk_cr2 = CLK_CR3;
        clk->clk_cr3 = CLK_OENAB|CLK_8BIT;
        clk->clk_cr2 = CLK_CR1;
        clk->clk_cr1 = CLK_IENAB;
}

void
stopclock(void)
{
        register struct clkreg *clk = (struct clkreg *)clkstd[0];

        clk->clk_cr2 = CLK_CR3;
        clk->clk_cr3 = 0;
        clk->clk_cr2 = CLK_CR1;
        clk->clk_cr1 = CLK_IENAB;
}
#endif

#endif


#ifdef PROFTIMER
/*
 * This code allows the amiga kernel to use one of the extra timers on
 * the clock chip for profiling, instead of the regular system timer.
 * The advantage of this is that the profiling timer can be turned up to
 * a higher interrupt rate, giving finer resolution timing. The profclock
 * routine is called from the lev6intr in locore, and is a specialized
 * routine that calls addupc. The overhead then is far less than if
 * hardclock/softclock was called. Further, the context switch code in
 * locore has been changed to turn the profile clock on/off when switching
 * into/out of a process that is profiling (startprofclock/stopprofclock).
 * This reduces the impact of the profiling clock on other users, and might
 * possibly increase the accuracy of the profiling.
 */
int  profint   = PRF_INTERVAL;  /* Clock ticks between interrupts */
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)
{
#if NCLOCK > 0
        struct proc *p = curproc;               /* XXX */

        /*
         * If the high-res timer is running, force profiling off.
         * Unfortunately, this gets reflected back to the user not as
         * an error but as a lack of results.
         */
        if (clockon) {
                p->p_stats->p_prof.pr_scale = 0;
                return;
        }
        /*
         * Keep track of the number of user processes that are profiling
         * by checking the scale value.
         *
         * XXX: this all assumes that the profiling code is well behaved;
         * i.e. profil() is called once per process with pcscale non-zero
         * to turn it on, and once with pcscale zero to turn it off.
         * Also assumes you don't do any forks or execs.  Oh well, there
         * is always adb...
         */
        if (p->p_stats->p_prof.pr_scale)
                profprocs++;
        else
                profprocs--;
#endif
        /*
         * The profile interrupt interval must be an even divisor
         * of the amiga_clk_interval so that scaling from a system clock
         * tick to a profile clock tick is possible using integer math.
         */
        if (profint > amiga_clk_interval || (amiga_clk_interval % profint) != 0)
                profint = amiga_clk_interval;
        profscale = amiga_clk_interval / profint;
}

void
startprofclock(void)
{
  unsigned short interval;

  /* stop timer B */
  clockcia->crb = clockcia->crb & 0xc0;

  /* load interval into registers.
     the clocks run at NTSC: 715.909kHz or PAL: 709.379kHz */

  interval = profint - 1;

  /* order of setting is important ! */
  clockcia->tblo = interval & 0xff;
  clockcia->tbhi = interval >> 8;

  /* enable interrupts for timer B */
  clockcia->icr = (1<<7) | (1<<1);

  /* start timer B in continuous shot mode */
  clockcia->crb = (clockcia->crb & 0xc0) | 1;
}

void
stopprofclock(void)
{
  /* stop timer B */
  clockcia->crb = clockcia->crb & 0xc0;
}

#ifdef PROF
/*
 * profclock() is expanded in line in lev6intr() unless profiling kernel.
 * Assumes it is called with clock interrupts blocked.
 */
void
profclock(void *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
#endif