mc146818.c

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    1 /*-
    2  * Copyright (c) 2003 Izumi Tsutsui.  All rights reserved.
    3  *
    4  * Redistribution and use in source and binary forms, with or without
    5  * modification, are permitted provided that the following conditions
    6  * are met:
    7  * 1. Redistributions of source code must retain the above copyright
    8  *    notice, this list of conditions and the following disclaimer.
    9  * 2. Redistributions in binary form must reproduce the above copyright
   10  *    notice, this list of conditions and the following disclaimer in the
   11  *    documentation and/or other materials provided with the distribution.
   12  * 3. The name of the author may not be used to endorse or promote products
   13  *    derived from this software without specific prior written permission.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   25  *
   26  *      from: NetBSD: mc146818.c,v 1.4 2003/11/24 06:20:40 tsutsui Exp
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 __FBSDID("$FreeBSD$");
   31 
   32 /*
   33  * mc146818 and compatible time of day chip subroutines
   34  */
   35 
   36 #include <sys/param.h>
   37 #include <sys/systm.h>
   38 #include <sys/bus.h>
   39 #include <sys/clock.h>
   40 #include <sys/lock.h>
   41 #include <sys/mutex.h>
   42 
   43 #include <machine/bus.h>
   44 
   45 #include <dev/mc146818/mc146818reg.h>
   46 #include <dev/mc146818/mc146818var.h>
   47 
   48 #include "clock_if.h"
   49 
   50 static u_int    mc146818_def_getcent(device_t);
   51 static void     mc146818_def_setcent(device_t, u_int);
   52 
   53 int
   54 mc146818_attach(device_t dev)
   55 {
   56         struct mc146818_softc *sc;
   57 
   58         sc = device_get_softc(dev);
   59 
   60         if (mtx_initialized(&sc->sc_mtx) == 0) {
   61                 device_printf(dev, "%s: mutex not initialized\n", __func__);
   62                 return (ENXIO);
   63         }
   64 
   65         if (sc->sc_mcread == NULL)
   66                 sc->sc_mcread = mc146818_def_read;
   67         if (sc->sc_mcwrite == NULL)
   68                 sc->sc_mcwrite = mc146818_def_write;
   69 
   70         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
   71                 /*
   72                  * Note that setting MC146818_NO_CENT_ADJUST means that
   73                  * the century has to be stored in NVRAM somewhere.
   74                  */
   75                 if (sc->sc_getcent == NULL)
   76                         sc->sc_getcent = mc146818_def_getcent;
   77                 if (sc->sc_setcent == NULL)
   78                         sc->sc_setcent = mc146818_def_setcent;
   79         }
   80 
   81         mtx_lock_spin(&sc->sc_mtx);
   82         if (!(*sc->sc_mcread)(dev, MC_REGD) & MC_REGD_VRT) {
   83                 mtx_unlock_spin(&sc->sc_mtx);
   84                 device_printf(dev, "%s: battery low\n", __func__);
   85                 return (ENXIO);
   86         }
   87 
   88         sc->sc_rega = MC_BASE_32_KHz;
   89         (*sc->sc_mcwrite)(dev, MC_REGA, sc->sc_rega);
   90 
   91         sc->sc_regb = 0;
   92         sc->sc_regb |= (sc->sc_flag & MC146818_BCD) ? 0 : MC_REGB_BINARY;
   93         sc->sc_regb |= (sc->sc_flag & MC146818_12HR) ? 0 : MC_REGB_24HR;
   94         (*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
   95         mtx_unlock_spin(&sc->sc_mtx);
   96 
   97         clock_register(dev, 1000000);   /* 1 second resolution. */
   98 
   99         return (0);
  100 }
  101 
  102 /*
  103  * Get time of day and convert it to a struct timespec.
  104  * Return 0 on success, an error number otherwise.
  105  */
  106 int
  107 mc146818_gettime(device_t dev, struct timespec *ts)
  108 {
  109         struct mc146818_softc *sc;
  110         struct clocktime ct;
  111         int timeout, cent, year;
  112 
  113         sc = device_get_softc(dev);
  114 
  115         timeout = 1000000;      /* XXX how long should we wait? */
  116 
  117         /*
  118          * If MC_REGA_UIP is 0 we have at least 244us before the next
  119          * update. If it's 1 an update is imminent.
  120          */
  121         for (;;) {
  122                 mtx_lock_spin(&sc->sc_mtx);
  123                 if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP))
  124                         break;
  125                 mtx_unlock_spin(&sc->sc_mtx);
  126                 if (--timeout < 0) {
  127                         device_printf(dev, "%s: timeout\n", __func__);
  128                         return (EBUSY);
  129                 }
  130         }
  131 
  132 #define FROMREG(x)      ((sc->sc_flag & MC146818_BCD) ? FROMBCD(x) : (x))
  133 
  134         ct.nsec = 0;
  135         ct.sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
  136         ct.min = FROMREG((*sc->sc_mcread)(dev, MC_MIN));
  137         ct.hour = FROMREG((*sc->sc_mcread)(dev, MC_HOUR));
  138         /* Map dow from 1 - 7 to 0 - 6. */
  139         ct.dow = FROMREG((*sc->sc_mcread)(dev, MC_DOW)) - 1;
  140         ct.day = FROMREG((*sc->sc_mcread)(dev, MC_DOM));
  141         ct.mon = FROMREG((*sc->sc_mcread)(dev, MC_MONTH));
  142         year = FROMREG((*sc->sc_mcread)(dev, MC_YEAR));
  143         year += sc->sc_year0;
  144         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
  145                 cent = (*sc->sc_getcent)(dev);
  146                 year += cent * 100;
  147         } else if (year < POSIX_BASE_YEAR)
  148                 year += 100;
  149         mtx_unlock_spin(&sc->sc_mtx);
  150 
  151         ct.year = year;
  152 
  153         return (clock_ct_to_ts(&ct, ts));
  154 }
  155 
  156 #ifdef notyet
  157 int
  158 mc146818_getsecs(device_t dev, int *secp)
  159 {
  160         struct mc146818_softc *sc;
  161         int sec, timeout;
  162 
  163         sc = device_get_softc(dev);
  164 
  165         timeout = 1000000;      /* XXX how long should we wait? */
  166 
  167         for (;;) {
  168                 mtx_lock_spin(&sc->sc_mtx);
  169                 if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP)) {
  170                         sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
  171                         mtx_unlock_spin(&sc->sc_mtx);
  172                         break;
  173                 }
  174                 mtx_unlock_spin(&sc->sc_mtx);
  175                 if (--timeout == 0) {
  176                         device_printf(dev, "%s: timeout\n", __func__);
  177                         return (EBUSY);
  178                 }
  179         }
  180 
  181 #undef FROMREG
  182 
  183         *secp = sec;
  184         return (0);
  185 }
  186 #endif
  187 
  188 /*
  189  * Set the time of day clock based on the value of the struct timespec arg.
  190  * Return 0 on success, an error number otherwise.
  191  */
  192 int
  193 mc146818_settime(device_t dev, struct timespec *ts)
  194 {
  195         struct mc146818_softc *sc;
  196         struct clocktime ct;
  197         int cent, year;
  198 
  199         sc = device_get_softc(dev);
  200 
  201         /* Accuracy is only one second. */
  202         if (ts->tv_nsec >= 500000000)
  203                 ts->tv_sec++;
  204         ts->tv_nsec = 0;
  205         clock_ts_to_ct(ts, &ct);
  206 
  207         mtx_lock_spin(&sc->sc_mtx);
  208         /* Disable RTC updates and interrupts (if enabled). */
  209         (*sc->sc_mcwrite)(dev, MC_REGB,
  210             ((sc->sc_regb & (MC_REGB_BINARY | MC_REGB_24HR)) | MC_REGB_SET));
  211 
  212 #define TOREG(x)        ((sc->sc_flag & MC146818_BCD) ? TOBCD(x) : (x))
  213 
  214         (*sc->sc_mcwrite)(dev, MC_SEC, TOREG(ct.sec));
  215         (*sc->sc_mcwrite)(dev, MC_MIN, TOREG(ct.min));
  216         (*sc->sc_mcwrite)(dev, MC_HOUR, TOREG(ct.hour));
  217         /* Map dow from 0 - 6 to 1 - 7. */
  218         (*sc->sc_mcwrite)(dev, MC_DOW, TOREG(ct.dow + 1));
  219         (*sc->sc_mcwrite)(dev, MC_DOM, TOREG(ct.day));
  220         (*sc->sc_mcwrite)(dev, MC_MONTH, TOREG(ct.mon));
  221 
  222         year = ct.year - sc->sc_year0;
  223         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
  224                 cent = year / 100;
  225                 (*sc->sc_setcent)(dev, cent);
  226                 year -= cent * 100;
  227         } else if (year > 99)
  228                 year -= 100;
  229         (*sc->sc_mcwrite)(dev, MC_YEAR, TOREG(year));
  230 
  231         /* Reenable RTC updates and interrupts. */
  232         (*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
  233         mtx_unlock_spin(&sc->sc_mtx);
  234 
  235 #undef TOREG
  236 
  237         return (0);
  238 }
  239 
  240 #define MC_ADDR 0
  241 #define MC_DATA 1
  242 
  243 u_int
  244 mc146818_def_read(device_t dev, u_int reg)
  245 {
  246         struct mc146818_softc *sc;
  247 
  248         sc = device_get_softc(dev);
  249         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
  250         return (bus_space_read_1(sc->sc_bst, sc->sc_bsh, MC_DATA));
  251 }
  252 
  253 void
  254 mc146818_def_write(device_t dev, u_int reg, u_int val)
  255 {
  256         struct mc146818_softc *sc;
  257 
  258         sc = device_get_softc(dev);
  259         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
  260         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_DATA, val);
  261 }
  262 
  263 /*
  264  * Looks like it's common even across platforms to store the century at
  265  * 0x32 in the NVRAM of the mc146818.
  266  */
  267 #define MC_CENT 0x32
  268 
  269 static u_int
  270 mc146818_def_getcent(device_t dev)
  271 {
  272         struct mc146818_softc *sc;
  273 
  274         sc = device_get_softc(dev);
  275         return ((*sc->sc_mcread)(dev, MC_CENT));
  276 }
  277 
  278 static void
  279 mc146818_def_setcent(device_t dev, u_int cent)
  280 {
  281         struct mc146818_softc *sc;
  282 
  283         sc = device_get_softc(dev);
  284         (*sc->sc_mcwrite)(dev, MC_CENT, cent);
  285 }

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FreeBSD/Linux Kernel Cross Reference sys/dev/mc146818/mc146818.c

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sys/dev/mc146818/mc146818.c