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rambo.c revision 1.2 
      1 /*	$NetBSD: rambo.c,v 1.2 2000/08/15 04:56:47 wdk 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  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/param.h>
     40 #include <sys/kernel.h>
     41 #include <sys/device.h>
     42 #include <sys/systm.h>
     43 
     44 #include <machine/cpu.h>
     45 #include <machine/mainboard.h>
     46 #include <machine/autoconf.h>
     47 #include <machine/sysconf.h>
     48 #include <machine/bus.h>
     49 
     50 #include <mipsco/obio/rambo.h>
     51 
     52 /*
     53  * Timer & Interrupt manipulation routines for the Rambo Custom ASIC
     54  */
     55 
     56 static int	rambo_match  __P((struct device *, struct cfdata *, void *));
     57 static void	rambo_attach __P((struct device *, struct device *, void *));
     58 static unsigned rambo_clkread __P((void));
     59 void rambo_clkintr __P((struct clockframe *));
     60 
     61 struct rambo_softc {
     62         struct device		dev;
     63 	struct evcnt		sc_intrcnt;
     64 	bus_space_tag_t		sc_bst;
     65 	bus_space_handle_t	sc_bsh;
     66 	u_int32_t		sc_tclast;
     67 	u_int32_t		sc_hzticks;
     68 };
     69 
     70 static struct rambo_softc *rambo;
     71 
     72 struct cfattach rambo_ca = {
     73 	sizeof(struct rambo_softc), rambo_match, rambo_attach
     74 };
     75 
     76 static int
     77 rambo_match(parent, cf, aux)
     78 	struct device *parent;
     79 	struct cfdata *cf;
     80 	void *aux;
     81 {
     82 	return 1;
     83 }
     84 
     85 static void
     86 rambo_attach(parent, self, aux)
     87 	struct device *parent, *self;
     88 	void *aux;
     89 {
     90 	struct confargs *ca = aux;
     91 	struct rambo_softc *sc = (void *)self;
     92 
     93 	sc->sc_bst = ca->ca_bustag;
     94 
     95 	if (bus_space_map(ca->ca_bustag, ca->ca_addr, 256,
     96 			  BUS_SPACE_MAP_LINEAR,
     97 			  &sc->sc_bsh) != 0) {
     98 		printf(": cannot map registers\n");
     99 		return;
    100 	}
    101 	evcnt_attach_dynamic(&sc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
    102 			     "timer", "intr");
    103 
    104 	/* Setup RAMBO Timer to generate timer interrupts */
    105 	sc->sc_hzticks = HZ_TO_TICKS(hz);
    106 
    107 	sc->sc_tclast = sc->sc_hzticks;
    108 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TCOUNT, 0);
    109 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TBREAK, sc->sc_hzticks);
    110 
    111 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_CTLREG,
    112 			  RB_PARITY_EN | RB_BUZZOFF | RB_CLR_IOERR);
    113 
    114 	printf(": parity enabled\n");
    115 	rambo = sc;
    116 	platform.clkread = rambo_clkread;
    117 }
    118 
    119 void
    120 rambo_clkintr(cf)
    121 	struct clockframe *cf;
    122 {
    123 	register u_int32_t tbreak, tclast;
    124 	register int cycles = 0;
    125 
    126 	rambo->sc_intrcnt.ev_count++;
    127 	tbreak = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK);
    128 	/* This will also clear the interrupt */
    129 	while ((tclast=bus_space_read_4(rambo->sc_bst, rambo->sc_bsh,
    130 					RB_TCOUNT)) >= tbreak) {
    131 		hardclock(cf);
    132 		tbreak += rambo->sc_hzticks;
    133 		cycles++;
    134 	}
    135 
    136 	bus_space_write_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK, tbreak);
    137 	rambo->sc_tclast = tclast;
    138 }
    139 
    140 /*
    141  * Calculate the number of microseconds since the last clock tick
    142  */
    143 unsigned
    144 rambo_clkread()
    145 {
    146         register u_int32_t tcount;
    147 	register u_int32_t tusec;
    148 
    149 	int s = splclock();
    150 	tcount = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TCOUNT);
    151 	tusec  = TICKS_TO_USECS(tcount-rambo->sc_tclast, hz);
    152 	splx(s);
    153 
    154 	return tusec;
    155 }
    156