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rambo.c revision 1.13 
      1 /*	$NetBSD: rambo.c,v 1.13 2012/10/27 17:18:03 chs 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 1.13 2012/10/27 17:18:03 chs 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 	u_int32_t		sc_tclast;
     64 	u_int32_t		sc_hzticks;
     65 };
     66 
     67 static struct rambo_softc *rambo;
     68 
     69 CFATTACH_DECL_NEW(rambo, sizeof(struct rambo_softc),
     70     rambo_match, rambo_attach, NULL, NULL);
     71 
     72 static int
     73 rambo_match(device_t parent, cfdata_t cf, void *aux)
     74 {
     75 	return 1;
     76 }
     77 
     78 static void
     79 rambo_attach(device_t parent, device_t self, void *aux)
     80 {
     81 	struct confargs *ca = aux;
     82 	struct rambo_softc *sc = device_private(self);
     83 
     84 	sc->sc_bst = ca->ca_bustag;
     85 
     86 	if (bus_space_map(ca->ca_bustag, ca->ca_addr, 256,
     87 			  BUS_SPACE_MAP_LINEAR,
     88 			  &sc->sc_bsh) != 0) {
     89 		printf(": cannot map registers\n");
     90 		return;
     91 	}
     92 	evcnt_attach_dynamic(&sc->sc_intrcnt, EVCNT_TYPE_INTR, NULL,
     93 			     "timer", "intr");
     94 
     95 	/* Setup RAMBO Timer to generate timer interrupts */
     96 	sc->sc_hzticks = HZ_TO_TICKS(hz);
     97 
     98 	sc->sc_tclast = 0;
     99 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TCOUNT, 0);
    100 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_TBREAK, sc->sc_hzticks);
    101 
    102 	bus_space_write_4(sc->sc_bst, sc->sc_bsh, RB_CTLREG,
    103 			  RB_PARITY_EN | RB_BUZZOFF | RB_CLR_IOERR);
    104 
    105 	printf(": parity enabled\n");
    106 	rambo = sc;
    107 	platform.clkinit = rambo_tc_init;
    108 }
    109 
    110 void
    111 rambo_clkintr(struct clockframe *cf)
    112 {
    113 	register u_int32_t tbreak, tcount;
    114 	register int delta;
    115 
    116 	rambo->sc_intrcnt.ev_count++;
    117 	tbreak = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK);
    118 	tcount = bus_space_read_4(rambo->sc_bst, rambo->sc_bsh,	RB_TCOUNT);
    119 	delta  = tcount - tbreak;
    120 
    121 	if (delta > (rambo->sc_hzticks>>1)) {
    122 		/*
    123 		 * Either tcount may overtake the updated tbreak value
    124 		 * or we have missed several interrupt's
    125 		 */
    126 		int cycles = 10 * hz;
    127 		while (cycles && tbreak < tcount) {
    128 			hardclock(cf);
    129 			rambo->sc_tclast = tbreak;
    130 			tbreak += rambo->sc_hzticks;
    131 			cycles--;
    132 		}
    133 		if (cycles == 0) { /* catchup failed - assume we are in sync */
    134 			tcount = bus_space_read_4(rambo->sc_bst,
    135 						  rambo->sc_bsh, RB_TCOUNT);
    136 			rambo->sc_tclast = tbreak = tcount;
    137 		}
    138 	} else {
    139 		hardclock(cf);
    140 		rambo->sc_tclast = tbreak;
    141 	}
    142 
    143 	tbreak += rambo->sc_hzticks;
    144 
    145 	bus_space_write_4(rambo->sc_bst, rambo->sc_bsh, RB_TBREAK, tbreak);
    146 }
    147 
    148 /*
    149  * Calculate the number of microseconds since the last clock tick
    150  */
    151 static unsigned
    152 rambo_get_timecount(struct timecounter *tc)
    153 {
    154 
    155 	return (bus_space_read_4(rambo->sc_bst, rambo->sc_bsh, RB_TCOUNT));
    156 }
    157 
    158 static void
    159 rambo_tc_init(void)
    160 {
    161 	static struct timecounter tc = {
    162 		.tc_get_timecount = rambo_get_timecount,
    163 		.tc_frequency = RB_FREQUENCY,
    164 		.tc_quality = 100,
    165 		.tc_name = "rambo_tcount",
    166 		.tc_counter_mask = ~0
    167 	};
    168 
    169 	tc_init(&tc);
    170 }
    171