/*      $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);
}