mcclock.c revision 1.21
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 (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 1.21 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 } 246
Indexes created Thu Sep 25 16:09:42 GMT 2025