/*      $NetBSD: rambo.c,v 1.15 2025/05/01 05:36:02 tsutsui Exp $       */

/*
 * Copyright (c) 2000 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Wayne Knowles
 *
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: rambo.c,v 1.15 2025/05/01 05:36:02 tsutsui Exp $");

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

#include <machine/cpu.h>
#include <machine/mainboard.h>
#include <machine/autoconf.h>
#include <machine/sysconf.h>
#include <machine/bus.h>

#include <mipsco/obio/rambo.h>

/*
 * Timer & Interrupt manipulation routines for the Rambo Custom ASIC 
 */

static int      rambo_match(device_t, cfdata_t, void *);
static void     rambo_attach(device_t, device_t, void *);
static unsigned rambo_get_timecount(struct timecounter *);
void rambo_clkintr(struct clockframe *);
static void rambo_tc_init(void);

struct rambo_softc {
        struct evcnt            sc_intrcnt;
        bus_space_tag_t         sc_bst;
        bus_space_handle_t      sc_bsh;
        uint32_t                sc_hzticks;
};

static struct rambo_softc *rambo;

CFATTACH_DECL_NEW(rambo, sizeof(struct rambo_softc),
    rambo_match, rambo_attach, NULL, NULL);

static int
rambo_match(device_t parent, cfdata_t cf, void *aux)
{
        return 1;
}

static void
rambo_attach(device_t parent, device_t self, void *aux)
{
        struct confargs *ca = aux;
        struct rambo_softc *sc = device_private(self);

        sc->sc_bst = ca->ca_bustag;

        if (bus_space_map(ca->ca_bustag, ca->ca_addr, 256,
                          BUS_SPACE_MAP_LINEAR,
                          &sc->sc_bsh) != 0) {
                printf(": cannot map registers\n");
                return;
        }
        evcnt_attach_dynamic(&sc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
                             "timer", "intr");

        /* Setup RAMBO Timer to generate timer interrupts */
        sc->sc_hzticks = HZ_TO_TICKS(hz);

        bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TCOUNT, 0);
        bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TBREAK, sc->sc_hzticks);

        bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_CTLREG,
                          RB_PARITY_EN | RB_BUZZOFF | RB_CLR_IOERR);

        printf(": parity enabled\n");
        rambo = sc;
        platform.clkinit = rambo_tc_init;
}

void
rambo_clkintr(struct clockframe *cf)
{
        register uint32_t tbreak, tcount;
        register int delta;

        rambo->sc_intrcnt.ev_count++;
        tbreak = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK);
        tcount = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TCOUNT);
        delta  = tcount - tbreak;

        if (delta > (rambo->sc_hzticks>>1)) {
                /*
                 * Either tcount may overtake the updated tbreak value
                 * or we have missed several interrupts.
                 */
                int cycles = 10 * hz;
                while (cycles && tbreak < tcount) {
                        hardclock(cf);
                        tbreak += rambo->sc_hzticks;
                        cycles--;
                }
        } else {
                hardclock(cf);
                tbreak += rambo->sc_hzticks;
        }

        bus_space_write_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK, tbreak);
}    

static unsigned
rambo_get_timecount(struct timecounter *tc)
{

        return (bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TCOUNT));
}

static void
rambo_tc_init(void)
{
        static struct timecounter tc = {
                .tc_get_timecount = rambo_get_timecount,
                .tc_frequency = RB_FREQUENCY,
                .tc_quality = 100,
                .tc_name = "rambo_tcount",
                .tc_counter_mask = ~0
        };

        tc_init(&tc);
}