sys/dev/dec/mcclock.c

   1 /* $NetBSD: mcclock.c,v 1.23 2009/05/12 14:18:16 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 1.23 2009/05/12 14:18:16 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(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(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(struct mcclock_softc *sc, const struct mcclock_busfns *busfns)
  69 {
  70
  71         printf(": 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         sc->sc_todr.cookie = sc;
  83         todr_attach(&sc->sc_todr);
  84 }
  85
  86 void
  87 mcclock_init(device_t dev)
  88 {
  89         struct mcclock_softc *sc = (struct mcclock_softc *)dev;
  90         int rate;
  91
  92 again:
  93         switch (hz) {
  94         case 32:
  95                 rate = MC_BASE_32_KHz | MC_RATE_32_Hz;
  96                 break;
  97         case 64:
  98                 rate = MC_BASE_32_KHz | MC_RATE_64_Hz;
  99                 break;
 100         case 128:
 101                 rate = MC_BASE_32_KHz | MC_RATE_128_Hz;
 102                 break;
 103         case 256:
 104                 rate = MC_BASE_32_KHz | MC_RATE_256_Hz;
 105                 break;
 106         case 512:
 107                 rate = MC_BASE_32_KHz | MC_RATE_512_Hz;
 108                 break;
 109         case 1024:
 110                 rate = MC_BASE_32_KHz | MC_RATE_1024_Hz;
 111                 break;
 112         case 2048:
 113                 rate = MC_BASE_32_KHz | MC_RATE_2048_Hz;
 114                 break;
 115         case 4096:
 116                 rate = MC_BASE_32_KHz | MC_RATE_4096_Hz;
 117                 break;
 118         case 8192:
 119                 rate = MC_BASE_32_KHz | MC_RATE_8192_Hz;
 120                 break;
 121         case 16384:
 122                 rate = MC_BASE_4_MHz | MC_RATE_1;
 123                 break;
 124         case 32768:
 125                 rate = MC_BASE_4_MHz | MC_RATE_2;
 126                 break;
 127         default:
 128                 printf("%s: Cannot get %d Hz clock; using %d Hz\n",
 129                     device_xname(&sc->sc_dev), hz, MC_DEFAULTHZ);
 130                 hz = MC_DEFAULTHZ;
 131                 goto again;
 132         }
 133         mc146818_write(sc, MC_REGA, rate);
 134         mc146818_write(sc, MC_REGB,
 135             MC_REGB_PIE | MC_REGB_SQWE | MC_REGB_BINARY | MC_REGB_24HR);
 136 }
 137
 138 /*
 139  * Experiments (and  passing years) show that Decstation PROMS
 140  * assume the kernel uses the clock chip as a time-of-year clock.
 141  * The PROM assumes the clock is always set to 1972 or 1973, and contains
 142  * time-of-year in seconds.   The PROM checks the clock at boot time,
 143  * and if it's outside that range, sets it to 1972-01-01.
 144  *
 145  * XXX should be at the mc146818 layer?
 146 */
 147
 148 /*
 149  * Get the time of day, based on the clock's value and/or the base value.
 150  */
 151 int
 152 mcclock_get(todr_chip_handle_t tch, struct timeval *tvp)
 153 {
 154         struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
 155         uint32_t yearsecs;
 156         mc_todregs regs;
 157         int s;
 158         struct clock_ymdhms dt;
 159
 160         s = splclock();
 161         MC146818_GETTOD(sc, &regs)
 162         splx(s);
 163
 164         dt.dt_sec = regs[MC_SEC];
 165         dt.dt_min = regs[MC_MIN];
 166         dt.dt_hour = regs[MC_HOUR];
 167         dt.dt_day = regs[MC_DOM];
 168         dt.dt_mon = regs[MC_MONTH];
 169         dt.dt_year = 1972;
 170
 171         yearsecs = clock_ymdhms_to_secs(&dt) - (72 - 70) * SECYR;
 172
 173         /*
 174          * Take the actual year from the filesystem if possible;
 175          * allow for 2 days of clock loss and 363 days of clock gain.
 176          */
 177         dt.dt_year = 1972; /* or MINYEAR or base/SECYR+1970 ... */
 178         dt.dt_mon = 1;
 179         dt.dt_day = 1;
 180         dt.dt_hour = 0;
 181         dt.dt_min = 0;
 182         dt.dt_sec = 0;
 183         for(;;) {
 184                 tvp->tv_sec = yearsecs + clock_ymdhms_to_secs(&dt);
 185                 if (tvp->tv_sec > tch->base_time - 2 * SECDAY)
 186                         break;
 187                 dt.dt_year++;
 188         }
 189
 190         tvp->tv_usec = 0;
 191         return 0;
 192 }
 193
 194 /*
 195  * Reset the TODR based on the time value.
 196  */
 197 int
 198 mcclock_set(todr_chip_handle_t tch, struct timeval *tvp)
 199 {
 200         struct mcclock_softc *sc = (struct mcclock_softc *)tch->cookie;
 201         struct clock_ymdhms dt;
 202         uint32_t yearsecs;
 203         mc_todregs regs;
 204         int s;
 205
 206         /*
 207          * calculate seconds relative to this year
 208          */
 209         clock_secs_to_ymdhms(tvp->tv_sec, &dt); /* get the year */
 210         dt.dt_mon = 1;
 211         dt.dt_day = 1;
 212         dt.dt_hour = 0;
 213         dt.dt_min = 0;
 214         dt.dt_sec = 0;
 215         yearsecs = tvp->tv_sec - clock_ymdhms_to_secs(&dt);
 216
 217 #define first72 ((72 - 70) * SECYR)
 218         clock_secs_to_ymdhms(first72 + yearsecs, &dt);
 219
 220 #ifdef DEBUG
 221         if (dt.dt_year != 1972)
 222                 printf("resettodr: botch (%d, %ld)\n", yearsecs, time_second);
 223 #endif
 224
 225         s = splclock();
 226         MC146818_GETTOD(sc, &regs);
 227         splx(s);
 228
 229         regs[MC_SEC] = dt.dt_sec;
 230         regs[MC_MIN] = dt.dt_min;
 231         regs[MC_HOUR] = dt.dt_hour;
 232         regs[MC_DOW] = dt.dt_wday;
 233         regs[MC_DOM] = dt.dt_day;
 234         regs[MC_MONTH] = dt.dt_mon;
 235         regs[MC_YEAR] = dt.dt_year;
 236
 237         s = splclock();
 238         MC146818_PUTTOD(sc, &regs);
 239         splx(s);
 240
 241         return 0;
 242 }