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      1 /*	$NetBSD: rambo.c,v 1.15 2025/05/01 05:36:02 tsutsui Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2000 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Wayne Knowles
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: rambo.c,v 1.15 2025/05/01 05:36:02 tsutsui Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/kernel.h>
     37 #include <sys/device.h>
     38 #include <sys/systm.h>
     39 #include <sys/timetc.h>
     40 
     41 #include <machine/cpu.h>
     42 #include <machine/mainboard.h>
     43 #include <machine/autoconf.h>
     44 #include <machine/sysconf.h>
     45 #include <machine/bus.h>
     46 
     47 #include <mipsco/obio/rambo.h>
     48 
     49 /*
     50  * Timer & Interrupt manipulation routines for the Rambo Custom ASIC
     51  */
     52 
     53 static int	rambo_match(device_t, cfdata_t, void *);
     54 static void	rambo_attach(device_t, device_t, void *);
     55 static unsigned rambo_get_timecount(struct timecounter *);
     56 void rambo_clkintr(struct clockframe *);
     57 static void rambo_tc_init(void);
     58 
     59 struct rambo_softc {
     60 	struct evcnt		sc_intrcnt;
     61 	bus_space_tag_t		sc_bst;
     62 	bus_space_handle_t	sc_bsh;
     63 	uint32_t		sc_hzticks;
     64 };
     65 
     66 static struct rambo_softc *rambo;
     67 
     68 CFATTACH_DECL_NEW(rambo, sizeof(struct rambo_softc),
     69     rambo_match, rambo_attach, NULL, NULL);
     70 
     71 static int
     72 rambo_match(device_t parent, cfdata_t cf, void *aux)
     73 {
     74 	return 1;
     75 }
     76 
     77 static void
     78 rambo_attach(device_t parent, device_t self, void *aux)
     79 {
     80 	struct confargs *ca = aux;
     81 	struct rambo_softc *sc = device_private(self);
     82 
     83 	sc->sc_bst = ca->ca_bustag;
     84 
     85 	if (bus_space_map(ca->ca_bustag, ca->ca_addr, 256,
     86 			  BUS_SPACE_MAP_LINEAR,
     87 			  &sc->sc_bsh) != 0) {
     88 		printf(": cannot map registers\n");
     89 		return;
     90 	}
     91 	evcnt_attach_dynamic(&sc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
     92 			     "timer", "intr");
     93 
     94 	/* Setup RAMBO Timer to generate timer interrupts */
     95 	sc->sc_hzticks = HZ_TO_TICKS(hz);
     96 
     97 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TCOUNT, 0);
     98 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TBREAK, sc->sc_hzticks);
     99 
    100 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_CTLREG,
    101 			  RB_PARITY_EN | RB_BUZZOFF | RB_CLR_IOERR);
    102 
    103 	printf(": parity enabled\n");
    104 	rambo = sc;
    105 	platform.clkinit = rambo_tc_init;
    106 }
    107 
    108 void
    109 rambo_clkintr(struct clockframe *cf)
    110 {
    111 	register uint32_t tbreak, tcount;
    112 	register int delta;
    113 
    114 	rambo->sc_intrcnt.ev_count++;
    115 	tbreak = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK);
    116 	tcount = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh,	RB_TCOUNT);
    117 	delta  = tcount - tbreak;
    118 
    119 	if (delta > (rambo->sc_hzticks>>1)) {
    120 		/*
    121 		 * Either tcount may overtake the updated tbreak value
    122 		 * or we have missed several interrupts.
    123 		 */
    124 		int cycles = 10 * hz;
    125 		while (cycles && tbreak < tcount) {
    126 			hardclock(cf);
    127 			tbreak += rambo->sc_hzticks;
    128 			cycles--;
    129 		}
    130 	} else {
    131 		hardclock(cf);
    132 		tbreak += rambo->sc_hzticks;
    133 	}
    134 
    135 	bus_space_write_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK, tbreak);
    136 }
    137 
    138 static unsigned
    139 rambo_get_timecount(struct timecounter *tc)
    140 {
    141 
    142 	return (bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TCOUNT));
    143 }
    144 
    145 static void
    146 rambo_tc_init(void)
    147 {
    148 	static struct timecounter tc = {
    149 		.tc_get_timecount = rambo_get_timecount,
    150 		.tc_frequency = RB_FREQUENCY,
    151 		.tc_quality = 100,
    152 		.tc_name = "rambo_tcount",
    153 		.tc_counter_mask = ~0
    154 	};
    155 
    156 	tc_init(&tc);
    157 }
    158