mcclock.c revision 1.32
1 /* $NetBSD: mcclock.c,v 1.32 2025/09/07 21:45:15 thorpej 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 (at) 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 1.32 2025/09/07 21:45:15 thorpej 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_DEFAULTHZ 1024 48 #endif 49 #ifdef pmax 50 #define MC_DEFAULTHZ 256 51 #endif 52 53 54 void mcclock_init(device_t); 55 int mcclock_get(todr_chip_handle_t, struct timeval *); 56 int mcclock_set(todr_chip_handle_t, struct timeval *); 57 58 const struct clockfns mcclock_clockfns = { 59 mcclock_init, 60 }; 61 62 #define mc146818_write(sc, reg, datum) \ 63 (*(sc)->sc_busfns->mc_bf_write)(sc, reg, datum) 64 #define mc146818_read(sc, reg) \ 65 (*(sc)->sc_busfns->mc_bf_read)(sc, reg) 66 67 void 68 mcclock_attach(struct mcclock_softc *sc, const struct mcclock_busfns *busfns) 69 { 70 71 aprint_normal(": mc146818 or compatible"); 72 73 sc->sc_busfns = busfns; 74 75 /* Turn interrupts off, just in case. */ 76 mc146818_write(sc, MC_REGB, MC_REGB_BINARY | MC_REGB_24HR); 77 78 clockattach(sc->sc_dev, &mcclock_clockfns); 79 80 sc->sc_todr.todr_gettime = mcclock_get; 81 sc->sc_todr.todr_settime = mcclock_set; 82 KASSERT(sc->sc_dev != NULL); 83 sc->sc_todr.todr_dev = sc->sc_dev; 84 todr_attach(&sc->sc_todr); 85 } 86 87 void 88 mcclock_init(device_t dev) 89 { 90 struct mcclock_softc *sc = device_private(dev); 91 int rate; 92 93 again: 94 switch (hz) { 95 case 32: 96 rate = MC_BASE_32_KHz | MC_RATE_32_Hz; 97 break; 98 case 64: 99 rate = MC_BASE_32_KHz | MC_RATE_64_Hz; 100 break; 101 case 128: 102 rate = MC_BASE_32_KHz | MC_RATE_128_Hz; 103 break; 104 case 256: 105 rate = MC_BASE_32_KHz | MC_RATE_256_Hz; 106 break; 107 case 512: 108 rate = MC_BASE_32_KHz | MC_RATE_512_Hz; 109 break; 110 case 1024: 111 rate = MC_BASE_32_KHz | MC_RATE_1024_Hz; 112 break; 113 case 2048: 114 rate = MC_BASE_32_KHz | MC_RATE_2048_Hz; 115 break; 116 case 4096: 117 rate = MC_BASE_32_KHz | MC_RATE_4096_Hz; 118 break; 119 case 8192: 120 rate = MC_BASE_32_KHz | MC_RATE_8192_Hz; 121 break; 122 case 16384: 123 rate = MC_BASE_4_MHz | MC_RATE_1; 124 break; 125 case 32768: 126 rate = MC_BASE_4_MHz | MC_RATE_2; 127 break; 128 default: 129 printf("%s: Cannot get %d Hz clock; using %d Hz\n", 130 device_xname(dev), hz, MC_DEFAULTHZ); 131 hz = MC_DEFAULTHZ; 132 goto again; 133 } 134 mc146818_write(sc, MC_REGA, rate); 135 mc146818_write(sc, MC_REGB, 136 MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR); 137 } 138 139 /* 140 * Experiments (and passing years) show that Decstation PROMS 141 * assume the kernel uses the clock chip as a time-of-year clock. 142 * The PROM assumes the clock is always set to 1972 or 1973, and contains 143 * time-of-year in seconds. The PROM checks the clock at boot time, 144 * and if it's outside that range, sets it to 1972-01-01. 145 * 146 * XXX should be at the mc146818 layer? 147 */ 148 149 /* 150 * Get the time of day, based on the clock's value and/or the base value. 151 */ 152 int 153 mcclock_get(todr_chip_handle_t tch, struct timeval *tvp) 154 { 155 struct mcclock_softc *sc = device_private(tch->todr_dev); 156 uint32_t yearsecs; 157 mc_todregs regs; 158 int s; 159 struct clock_ymdhms dt; 160 161 s = splclock(); 162 MC146818_GETTOD(sc, ®s) 163 splx(s); 164 165 dt.dt_sec = regs[MC_SEC]; 166 dt.dt_min = regs[MC_MIN]; 167 dt.dt_hour = regs[MC_HOUR]; 168 dt.dt_day = regs[MC_DOM]; 169 dt.dt_mon = regs[MC_MONTH]; 170 dt.dt_year = 1972; 171 172 yearsecs = clock_ymdhms_to_secs(&dt) - (72 - 70) * SECS_PER_COMMON_YEAR; 173 174 /* 175 * Take the actual year from the filesystem if possible; 176 * allow for 2 days of clock loss and 363 days of clock gain. 177 */ 178 dt.dt_year = 1972; /* or MINYEAR or base/SECS_PER_COMMON_YEAR+1970... */ 179 dt.dt_mon = 1; 180 dt.dt_day = 1; 181 dt.dt_hour = 0; 182 dt.dt_min = 0; 183 dt.dt_sec = 0; 184 for(;;) { 185 tvp->tv_sec = yearsecs + clock_ymdhms_to_secs(&dt); 186 if (tvp->tv_sec > tch->todr_base_time - 2 * SECS_PER_DAY) 187 break; 188 dt.dt_year++; 189 } 190 191 tvp->tv_usec = 0; 192 return 0; 193 } 194 195 /* 196 * Reset the TODR based on the time value. 197 */ 198 int 199 mcclock_set(todr_chip_handle_t tch, struct timeval *tvp) 200 { 201 struct mcclock_softc *sc = device_private(tch->todr_dev); 202 struct clock_ymdhms dt; 203 uint32_t yearsecs; 204 mc_todregs regs; 205 int s; 206 207 /* 208 * calculate seconds relative to this year 209 */ 210 clock_secs_to_ymdhms(tvp->tv_sec, &dt); /* get the year */ 211 dt.dt_mon = 1; 212 dt.dt_day = 1; 213 dt.dt_hour = 0; 214 dt.dt_min = 0; 215 dt.dt_sec = 0; 216 yearsecs = tvp->tv_sec - clock_ymdhms_to_secs(&dt); 217 218 #define first72 ((72 - 70) * SECS_PER_COMMON_YEAR) 219 clock_secs_to_ymdhms(first72 + yearsecs, &dt); 220 221 #ifdef DEBUG 222 if (dt.dt_year != 1972) 223 printf("resettodr: botch (%d, %" PRId64 ")\n", 224 yearsecs, time_second); 225 #endif 226 227 s = splclock(); 228 MC146818_GETTOD(sc, ®s); 229 splx(s); 230 231 regs[MC_SEC] = dt.dt_sec; 232 regs[MC_MIN] = dt.dt_min; 233 regs[MC_HOUR] = dt.dt_hour; 234 regs[MC_DOW] = dt.dt_wday; 235 regs[MC_DOM] = dt.dt_day; 236 regs[MC_MONTH] = dt.dt_mon; 237 regs[MC_YEAR] = dt.dt_year - 1900; /* rt clock wants 2 digits */ 238 239 s = splclock(); 240 MC146818_PUTTOD(sc, ®s); 241 splx(s); 242 243 return 0; 244 } 245
Indexes created Fri Sep 26 08:10:20 GMT 2025