FreeBSD/Linux Kernel Cross Reference
sys/dev/dec/mcclock.c
1 /* $NetBSD: mcclock.c,v 1.21 2008/04/08 07:39:11 cegger Exp $ */
2
3 /*
4 * Copyright (c) 1994, 1995, 1996 Carnegie-Mellon University.
5 * All rights reserved.
6 *
7 * Author: Chris G. Demetriou
8 *
9 * Permission to use, copy, modify and distribute this software and
10 * its documentation is hereby granted, provided that both the copyright
11 * notice and this permission notice appear in all copies of the
12 * software, derivative works or modified versions, and any portions
13 * thereof, and that both notices appear in supporting documentation.
14 *
15 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
16 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
17 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
18 *
19 * Carnegie Mellon requests users of this software to return to
20 *
21 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
22 * School of Computer Science
23 * Carnegie Mellon University
24 * Pittsburgh PA 15213-3890
25 *
26 * any improvements or extensions that they make and grant Carnegie the
27 * rights to redistribute these changes.
28 */
29
30 #include <sys/cdefs.h>
31 __KERNEL_RCSID(0, "$NetBSD: mcclock.c,v 1.21 2008/04/08 07:39:11 cegger Exp $");
32
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/systm.h>
36 #include <sys/device.h>
37 #include <dev/clock_subr.h>
38
39 #include <dev/dec/clockvar.h>
40 #include <dev/dec/mcclockvar.h>
41 #include <dev/ic/mc146818reg.h>
42
43 /*
44 * XXX default rate is machine-dependent.
45 */
46 #ifdef __alpha__
47 #define MC_DFEAULTHZ 1024
48 #endif
49 #ifdef pmax
50 #define MC_DEFAULTHZ 256
51 #endif
52
53
54 void mcclock_init(struct device *);
55 int mcclock_get(todr_chip_handle_t, volatile struct timeval *);
56 int mcclock_set(todr_chip_handle_t, volatile struct timeval *);
57
58 const struct clockfns mcclock_clockfns = {
59 mcclock_init,
60 };
61
62 #define mc146818_write(dev, reg, datum) \
63 (*(dev)->sc_busfns->mc_bf_write)(dev, reg, datum)
64 #define mc146818_read(dev, reg) \
65 (*(dev)->sc_busfns->mc_bf_read)(dev, reg)
66
67 void
68 mcclock_attach(sc, busfns)
69 struct mcclock_softc *sc;
70 const struct mcclock_busfns *busfns;
71 {
72
73 printf(": mc146818 or compatible");
74
75 sc->sc_busfns = busfns;
76
77 /* Turn interrupts off, just in case. */
78 mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR);
79
80 clockattach(&sc->sc_dev, &mcclock_clockfns);
81
82 sc->sc_todr.todr_gettime = mcclock_get;
83 sc->sc_todr.todr_settime = mcclock_set;
84 sc->sc_todr.cookie = sc;
85 todr_attach(&sc->sc_todr);
86 }
87
88 void
89 mcclock_init(dev)
90 struct device *dev;
91 {
92 struct mcclock_softc *sc = (struct mcclock_softc *)dev;
93 int rate;
94
95 again:
96 switch (hz) {
97 case 32:
98 rate = MC_BASE_32_KHz | MC_RATE_32_Hz;
99 break;
100 case 64:
101 rate = MC_BASE_32_KHz | MC_RATE_64_Hz;
102 break;
103 case 128:
104 rate = MC_BASE_32_KHz | MC_RATE_128_Hz;
105 break;
106 case 256:
107 rate = MC_BASE_32_KHz | MC_RATE_256_Hz;
108 break;
109 case 512:
110 rate = MC_BASE_32_KHz | MC_RATE_512_Hz;
111 break;
112 case 1024:
113 rate = MC_BASE_32_KHz | MC_RATE_1024_Hz;
114 break;
115 case 2048:
116 rate = MC_BASE_32_KHz | MC_RATE_2048_Hz;
117 break;
118 case 4096:
119 rate = MC_BASE_32_KHz | MC_RATE_4096_Hz;
120 break;
121 case 8192:
122 rate = MC_BASE_32_KHz | MC_RATE_8192_Hz;
123 break;
124 case 16384:
125 rate = MC_BASE_4_MHz | MC_RATE_1;
126 break;
127 case 32768:
128 rate = MC_BASE_4_MHz | MC_RATE_2;
129 break;
130 default:
131 printf("%s: Cannot get %d Hz clock; using %d Hz\n",
132 device_xname(&sc->sc_dev), hz, MC_DEFAULTHZ);
133 hz = MC_DEFAULTHZ;
134 goto again;
135 }
136 mc146818_write(sc, MC_REGA, rate);
137 mc146818_write(sc, MC_REGB,
138 MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR);
139 }
140
141 /*
142 * Experiments (and passing years) show that Decstation PROMS
143 * assume the kernel uses the clock chip as a time-of-year clock.
144 * The PROM assumes the clock is always set to 1972 or 1973, and contains
145 * time-of-year in seconds. The PROM checks the clock at boot time,
146 * and if it's outside that range, sets it to 1972-01-01.
147 *
148 * XXX should be at the mc146818 layer?
149 */
150
151 /*
152 * Get the time of day, based on the clock's value and/or the base value.
153 */
154 int
155 mcclock_get(todr_chip_handle_t tch, volatile struct timeval *tvp)
156 {
157 struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
158 uint32_t yearsecs;
159 mc_todregs regs;
160 int s;
161 struct clock_ymdhms dt;
162
163 s = splclock();
164 MC146818_GETTOD(sc, ®s)
165 splx(s);
166
167 dt.dt_sec = regs[MC_SEC];
168 dt.dt_min = regs[MC_MIN];
169 dt.dt_hour = regs[MC_HOUR];
170 dt.dt_day = regs[MC_DOM];
171 dt.dt_mon = regs[MC_MONTH];
172 dt.dt_year = 1972;
173
174 yearsecs = clock_ymdhms_to_secs(&dt) - (72 - 70) * SECYR;
175
176 /*
177 * Take the actual year from the filesystem if possible;
178 * allow for 2 days of clock loss and 363 days of clock gain.
179 */
180 dt.dt_year = 1972; /* or MINYEAR or base/SECYR+1970 ... */
181 dt.dt_mon = 1;
182 dt.dt_day = 1;
183 dt.dt_hour = 0;
184 dt.dt_min = 0;
185 dt.dt_sec = 0;
186 for(;;) {
187 tvp->tv_sec = yearsecs + clock_ymdhms_to_secs(&dt);
188 if (tvp->tv_sec > tch->base_time - 2 * SECDAY)
189 break;
190 dt.dt_year++;
191 }
192
193 tvp->tv_usec = 0;
194 return 0;
195 }
196
197 /*
198 * Reset the TODR based on the time value.
199 */
200 int
201 mcclock_set(todr_chip_handle_t tch, volatile struct timeval *tvp)
202 {
203 struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
204 struct clock_ymdhms dt;
205 uint32_t yearsecs;
206 mc_todregs regs;
207 int s;
208
209 /*
210 * calculate seconds relative to this year
211 */
212 clock_secs_to_ymdhms(tvp->tv_sec, &dt); /* get the year */
213 dt.dt_mon = 1;
214 dt.dt_day = 1;
215 dt.dt_hour = 0;
216 dt.dt_min = 0;
217 dt.dt_sec = 0;
218 yearsecs = tvp->tv_sec - clock_ymdhms_to_secs(&dt);
219
220 #define first72 ((72 - 70) * SECYR)
221 clock_secs_to_ymdhms(first72 + yearsecs, &dt);
222
223 #ifdef DEBUG
224 if (dt.dt_year != 1972)
225 printf("resettodr: botch (%d, %ld)\n", yearsecs, time_second);
226 #endif
227
228 s = splclock();
229 MC146818_GETTOD(sc, ®s);
230 splx(s);
231
232 regs[MC_SEC] = dt.dt_sec;
233 regs[MC_MIN] = dt.dt_min;
234 regs[MC_HOUR] = dt.dt_hour;
235 regs[MC_DOW] = dt.dt_wday;
236 regs[MC_DOM] = dt.dt_day;
237 regs[MC_MONTH] = dt.dt_mon;
238 regs[MC_YEAR] = dt.dt_year;
239
240 s = splclock();
241 MC146818_PUTTOD(sc, ®s);
242 splx(s);
243
244 return 0;
245 }
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