/*      $NetBSD: clock_pcc.c,v 1.20 2012/10/27 17:18:04 chs Exp $       */

/*-
 * Copyright (c) 1996 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * Glue for the Peripheral Channel Controller timers and the
 * Mostek clock chip found on the MVME-147.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: clock_pcc.c,v 1.20 2012/10/27 17:18:04 chs Exp $");

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

#include <machine/psl.h>
#include <machine/bus.h>

#include <dev/mvme/clockvar.h>

#include <mvme68k/dev/pccreg.h>
#include <mvme68k/dev/pccvar.h>

#include "ioconf.h"

int clock_pcc_match(device_t, cfdata_t, void *);
void clock_pcc_attach(device_t, device_t, void *);

struct clock_pcc_softc {
        struct clock_attach_args sc_clock_args;
        u_char sc_clock_lvl;
        struct timecounter sc_tc;
};

CFATTACH_DECL_NEW(clock_pcc, sizeof(struct clock_pcc_softc),
    clock_pcc_match, clock_pcc_attach, NULL, NULL);


static int clock_pcc_profintr(void *);
static int clock_pcc_statintr(void *);
static void clock_pcc_initclocks(void *, int, int);
static u_int clock_pcc_getcount(struct timecounter *);
static void clock_pcc_shutdown(void *);

static struct clock_pcc_softc *clock_pcc_sc;
static uint32_t clock_pcc_count;
static uint16_t clock_pcc_reload;

/* ARGSUSED */
int
clock_pcc_match(device_t parent, cfdata_t cf, void *aux)
{
        struct pcc_attach_args *pa;

        pa = aux;

        /* Only one clock, please. */
        if (clock_pcc_sc)
                return 0;

        if (strcmp(pa->pa_name, clock_cd.cd_name))
                return 0;

        pa->pa_ipl = cf->pcccf_ipl;

        return 1;
}

/* ARGSUSED */
void
clock_pcc_attach(device_t parent, device_t self, void *aux)
{
        struct pcc_attach_args *pa;
        struct clock_pcc_softc *sc;

        sc = device_private(self);
        pa = aux;

        if (pa->pa_ipl != CLOCK_LEVEL)
                panic("clock_pcc_attach: wrong interrupt level");

        clock_pcc_sc = sc;
        sc->sc_clock_args.ca_arg = sc;
        sc->sc_clock_args.ca_initfunc = clock_pcc_initclocks;

        /* Do common portions of clock config. */
        clock_config(self, &sc->sc_clock_args, pccintr_evcnt(pa->pa_ipl));

        /* Ensure our interrupts get disabled at shutdown time. */
        (void)shutdownhook_establish(clock_pcc_shutdown, NULL);

        /* Attach the interrupt handlers. */
        pccintr_establish(PCCV_TIMER1, clock_pcc_profintr, pa->pa_ipl,
            NULL, &clock_profcnt);
        pccintr_establish(PCCV_TIMER2, clock_pcc_statintr, pa->pa_ipl,
            NULL, &clock_statcnt);
        sc->sc_clock_lvl = pa->pa_ipl | PCC_IENABLE | PCC_TIMERACK;
}

void
clock_pcc_initclocks(void *arg, int prof_us, int stat_us)
{
        struct clock_pcc_softc *sc = arg;

        clock_pcc_reload = pcc_timer_us2lim(prof_us);
        pcc_reg_write16(sys_pcc, PCCREG_TMR1_PRELOAD, clock_pcc_reload);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_CONTROL, PCC_TIMERCLEAR);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_CONTROL, PCC_TIMERSTART);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_INTR_CTRL, sc->sc_clock_lvl);

        pcc_reg_write16(sys_pcc, PCCREG_TMR2_PRELOAD,
            pcc_timer_us2lim(stat_us));
        pcc_reg_write(sys_pcc, PCCREG_TMR2_CONTROL, PCC_TIMERCLEAR);
        pcc_reg_write(sys_pcc, PCCREG_TMR2_CONTROL, PCC_TIMERSTART);
        pcc_reg_write(sys_pcc, PCCREG_TMR2_INTR_CTRL, sc->sc_clock_lvl);

        sc->sc_tc.tc_get_timecount = clock_pcc_getcount;
        sc->sc_tc.tc_name = "pcc_count";
        sc->sc_tc.tc_frequency = PCC_TIMERFREQ;
        sc->sc_tc.tc_quality = 100;
        sc->sc_tc.tc_counter_mask = ~0;
        tc_init(&sc->sc_tc);
}

/* ARGSUSED */
u_int
clock_pcc_getcount(struct timecounter *tc)
{
        u_int cnt;
        uint16_t tc1, tc2;
        uint8_t cr;
        int s;

        s = splhigh();

        /*
         * There's no way to latch the counter and overflow registers
         * without pausing the clock, so compensate for the possible
         * race by checking for counter wrap-around and re-reading the
         * overflow counter if necessary.
         *
         * Note: This only works because we're at splhigh().
         */
        tc1 = pcc_reg_read16(sys_pcc, PCCREG_TMR1_COUNT);
        cr = pcc_reg_read(sys_pcc, PCCREG_TMR1_CONTROL);
        tc2 = pcc_reg_read16(sys_pcc, PCCREG_TMR1_COUNT);
        if (tc1 > tc2) {
                cr = pcc_reg_read(sys_pcc, PCCREG_TMR1_CONTROL);
                tc1 = tc2;
        }
        cnt = clock_pcc_count;
        splx(s);
        /* XXX assume HZ == 100 */
        cnt += (tc1 - clock_pcc_reload) +
            (PCC_TIMERFREQ / 100) * (cr >> PCC_TIMEROVFLSHIFT);

        return cnt;
}

int
clock_pcc_profintr(void *frame)
{
        uint8_t cr;
        uint16_t tc;
        int s;

        s = splhigh();
        tc = pcc_reg_read16(sys_pcc, PCCREG_TMR1_COUNT);
        cr = pcc_reg_read(sys_pcc, PCCREG_TMR1_CONTROL);
        if (tc > pcc_reg_read16(sys_pcc, PCCREG_TMR1_COUNT))
                cr = pcc_reg_read(sys_pcc, PCCREG_TMR1_CONTROL);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_CONTROL, PCC_TIMERSTART);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_INTR_CTRL,
            clock_pcc_sc->sc_clock_lvl);
        splx(s);

        for (cr >>= PCC_TIMEROVFLSHIFT; cr; cr--) {
                /* XXX assume HZ == 100 */
                clock_pcc_count += PCC_TIMERFREQ / 100;
                hardclock(frame);
        }

        return 1;
}

int
clock_pcc_statintr(void *frame)
{

        /* Disable the timer interrupt while we handle it. */
        pcc_reg_write(sys_pcc, PCCREG_TMR2_INTR_CTRL, 0);

        statclock((struct clockframe *) frame);

        pcc_reg_write16(sys_pcc, PCCREG_TMR2_PRELOAD,
            pcc_timer_us2lim(CLOCK_NEWINT(clock_statvar, clock_statmin)));
        pcc_reg_write(sys_pcc, PCCREG_TMR2_CONTROL, PCC_TIMERCLEAR);
        pcc_reg_write(sys_pcc, PCCREG_TMR2_CONTROL, PCC_TIMERSTART);

        pcc_reg_write(sys_pcc, PCCREG_TMR2_INTR_CTRL,
            clock_pcc_sc->sc_clock_lvl);

        return 1;
}

/* ARGSUSED */
void
clock_pcc_shutdown(void *arg)
{

        /* Make sure the timer interrupts are turned off. */
        pcc_reg_write(sys_pcc, PCCREG_TMR1_CONTROL, PCC_TIMERCLEAR);
        pcc_reg_write(sys_pcc, PCCREG_TMR1_INTR_CTRL, 0);
        pcc_reg_write(sys_pcc, PCCREG_TMR2_CONTROL, PCC_TIMERCLEAR);
        pcc_reg_write(sys_pcc, PCCREG_TMR2_INTR_CTRL, 0);
}