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
rambo_match(device_t parent,cfdata_t cf,void * aux)73 rambo_match(device_t parent, cfdata_t cf, void *aux)
74 {
75 return 1;
76 }
77
78 static void
rambo_attach(device_t parent,device_t self,void * aux)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
rambo_clkintr(struct clockframe * cf)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
rambo_get_timecount(struct timecounter * tc)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
rambo_tc_init(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