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  *
   13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
   22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   23  *
   24  *      $NetBSD: mc146818.c,v 1.16 2008/05/14 13:29:28 tsutsui Exp $
   25  */
   26 
   27 #include <sys/cdefs.h>
   28 __FBSDID("$FreeBSD$");
   29 
   30 /*
   31  * mc146818 and compatible time of day chip subroutines
   32  */
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/bus.h>
   37 #include <sys/clock.h>
   38 #include <sys/lock.h>
   39 #include <sys/mutex.h>
   40 
   41 #include <machine/bus.h>
   42 
   43 #include <dev/mc146818/mc146818reg.h>
   44 #include <dev/mc146818/mc146818var.h>
   45 
   46 #include "clock_if.h"
   47 
   48 static u_int    mc146818_def_getcent(device_t);
   49 static void     mc146818_def_setcent(device_t, u_int);
   50 
   51 int
   52 mc146818_attach(device_t dev)
   53 {
   54         struct mc146818_softc *sc;
   55 
   56         sc = device_get_softc(dev);
   57 
   58         if (mtx_initialized(&sc->sc_mtx) == 0) {
   59                 device_printf(dev, "%s: mutex not initialized\n", __func__);
   60                 return (ENXIO);
   61         }
   62 
   63         if (sc->sc_mcread == NULL)
   64                 sc->sc_mcread = mc146818_def_read;
   65         if (sc->sc_mcwrite == NULL)
   66                 sc->sc_mcwrite = mc146818_def_write;
   67 
   68         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
   69                 /*
   70                  * Note that setting MC146818_NO_CENT_ADJUST means that
   71                  * the century has to be stored in NVRAM somewhere.
   72                  */
   73                 if (sc->sc_getcent == NULL)
   74                         sc->sc_getcent = mc146818_def_getcent;
   75                 if (sc->sc_setcent == NULL)
   76                         sc->sc_setcent = mc146818_def_setcent;
   77         }
   78 
   79         mtx_lock_spin(&sc->sc_mtx);
   80         if (!(*sc->sc_mcread)(dev, MC_REGD) & MC_REGD_VRT) {
   81                 mtx_unlock_spin(&sc->sc_mtx);
   82                 device_printf(dev, "%s: battery low\n", __func__);
   83                 return (ENXIO);
   84         }
   85 
   86         sc->sc_rega = MC_BASE_32_KHz;
   87         (*sc->sc_mcwrite)(dev, MC_REGA, sc->sc_rega);
   88 
   89         sc->sc_regb = 0;
   90         sc->sc_regb |= (sc->sc_flag & MC146818_BCD) ? 0 : MC_REGB_BINARY;
   91         sc->sc_regb |= (sc->sc_flag & MC146818_12HR) ? 0 : MC_REGB_24HR;
   92         (*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
   93         mtx_unlock_spin(&sc->sc_mtx);
   94 
   95         clock_register(dev, 1000000);   /* 1 second resolution */
   96 
   97         return (0);
   98 }
   99 
  100 /*
  101  * Get time of day and convert it to a struct timespec.
  102  * Return 0 on success, an error number otherwise.
  103  */
  104 int
  105 mc146818_gettime(device_t dev, struct timespec *ts)
  106 {
  107         struct mc146818_softc *sc;
  108         struct clocktime ct;
  109         int timeout, cent, year;
  110 
  111         sc = device_get_softc(dev);
  112 
  113         timeout = 1000000;      /* XXX how long should we wait? */
  114 
  115         /*
  116          * If MC_REGA_UIP is 0 we have at least 244us before the next
  117          * update.  If it's 1 an update is imminent.
  118          */
  119         for (;;) {
  120                 mtx_lock_spin(&sc->sc_mtx);
  121                 if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP))
  122                         break;
  123                 mtx_unlock_spin(&sc->sc_mtx);
  124                 if (--timeout < 0) {
  125                         device_printf(dev, "%s: timeout\n", __func__);
  126                         return (EBUSY);
  127                 }
  128         }
  129 
  130 #define FROMREG(x)      ((sc->sc_flag & MC146818_BCD) ? FROMBCD(x) : (x))
  131 
  132         ct.nsec = 0;
  133         ct.sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
  134         ct.min = FROMREG((*sc->sc_mcread)(dev, MC_MIN));
  135         ct.hour = FROMREG((*sc->sc_mcread)(dev, MC_HOUR));
  136         /* Map dow from 1 - 7 to 0 - 6. */
  137         ct.dow = FROMREG((*sc->sc_mcread)(dev, MC_DOW)) - 1;
  138         ct.day = FROMREG((*sc->sc_mcread)(dev, MC_DOM));
  139         ct.mon = FROMREG((*sc->sc_mcread)(dev, MC_MONTH));
  140         year = FROMREG((*sc->sc_mcread)(dev, MC_YEAR));
  141         year += sc->sc_year0;
  142         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
  143                 cent = (*sc->sc_getcent)(dev);
  144                 year += cent * 100;
  145         } else if (year < POSIX_BASE_YEAR)
  146                 year += 100;
  147         mtx_unlock_spin(&sc->sc_mtx);
  148 
  149         ct.year = year;
  150 
  151         return (clock_ct_to_ts(&ct, ts));
  152 }
  153 
  154 #ifdef notyet
  155 int
  156 mc146818_getsecs(device_t dev, int *secp)
  157 {
  158         struct mc146818_softc *sc;
  159         int sec, timeout;
  160 
  161         sc = device_get_softc(dev);
  162 
  163         timeout = 1000000;      /* XXX how long should we wait? */
  164 
  165         for (;;) {
  166                 mtx_lock_spin(&sc->sc_mtx);
  167                 if (!((*sc->sc_mcread)(dev, MC_REGA) & MC_REGA_UIP)) {
  168                         sec = FROMREG((*sc->sc_mcread)(dev, MC_SEC));
  169                         mtx_unlock_spin(&sc->sc_mtx);
  170                         break;
  171                 }
  172                 mtx_unlock_spin(&sc->sc_mtx);
  173                 if (--timeout == 0) {
  174                         device_printf(dev, "%s: timeout\n", __func__);
  175                         return (EBUSY);
  176                 }
  177         }
  178 
  179 #undef FROMREG
  180 
  181         *secp = sec;
  182         return (0);
  183 }
  184 #endif
  185 
  186 /*
  187  * Set the time of day clock based on the value of the struct timespec arg.
  188  * Return 0 on success, an error number otherwise.
  189  */
  190 int
  191 mc146818_settime(device_t dev, struct timespec *ts)
  192 {
  193         struct mc146818_softc *sc;
  194         struct clocktime ct;
  195         int cent, year;
  196 
  197         sc = device_get_softc(dev);
  198 
  199         /* Accuracy is only one second. */
  200         if (ts->tv_nsec >= 500000000)
  201                 ts->tv_sec++;
  202         ts->tv_nsec = 0;
  203         clock_ts_to_ct(ts, &ct);
  204 
  205         mtx_lock_spin(&sc->sc_mtx);
  206         /* Disable RTC updates and interrupts (if enabled). */
  207         (*sc->sc_mcwrite)(dev, MC_REGB,
  208             ((sc->sc_regb & (MC_REGB_BINARY | MC_REGB_24HR)) | MC_REGB_SET));
  209 
  210 #define TOREG(x)        ((sc->sc_flag & MC146818_BCD) ? TOBCD(x) : (x))
  211 
  212         (*sc->sc_mcwrite)(dev, MC_SEC, TOREG(ct.sec));
  213         (*sc->sc_mcwrite)(dev, MC_MIN, TOREG(ct.min));
  214         (*sc->sc_mcwrite)(dev, MC_HOUR, TOREG(ct.hour));
  215         /* Map dow from 0 - 6 to 1 - 7. */
  216         (*sc->sc_mcwrite)(dev, MC_DOW, TOREG(ct.dow + 1));
  217         (*sc->sc_mcwrite)(dev, MC_DOM, TOREG(ct.day));
  218         (*sc->sc_mcwrite)(dev, MC_MONTH, TOREG(ct.mon));
  219 
  220         year = ct.year - sc->sc_year0;
  221         if (sc->sc_flag & MC146818_NO_CENT_ADJUST) {
  222                 cent = year / 100;
  223                 (*sc->sc_setcent)(dev, cent);
  224                 year -= cent * 100;
  225         } else if (year > 99)
  226                 year -= 100;
  227         (*sc->sc_mcwrite)(dev, MC_YEAR, TOREG(year));
  228 
  229         /* Reenable RTC updates and interrupts. */
  230         (*sc->sc_mcwrite)(dev, MC_REGB, sc->sc_regb);
  231         mtx_unlock_spin(&sc->sc_mtx);
  232 
  233 #undef TOREG
  234 
  235         return (0);
  236 }
  237 
  238 #define MC_ADDR 0
  239 #define MC_DATA 1
  240 
  241 u_int
  242 mc146818_def_read(device_t dev, u_int reg)
  243 {
  244         struct mc146818_softc *sc;
  245 
  246         sc = device_get_softc(dev);
  247         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
  248         return (bus_space_read_1(sc->sc_bst, sc->sc_bsh, MC_DATA));
  249 }
  250 
  251 void
  252 mc146818_def_write(device_t dev, u_int reg, u_int val)
  253 {
  254         struct mc146818_softc *sc;
  255 
  256         sc = device_get_softc(dev);
  257         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_ADDR, reg);
  258         bus_space_write_1(sc->sc_bst, sc->sc_bsh, MC_DATA, val);
  259 }
  260 
  261 #undef MC_ADDR
  262 #undef MC_DATA
  263 
  264 /*
  265  * Looks like it's common even across platforms to store the century at
  266  * 0x32 in the NVRAM of the mc146818.
  267  */
  268 #define MC_CENT 0x32
  269 
  270 static u_int
  271 mc146818_def_getcent(device_t dev)
  272 {
  273         struct mc146818_softc *sc;
  274 
  275         sc = device_get_softc(dev);
  276         return ((*sc->sc_mcread)(dev, MC_CENT));
  277 }
  278 
  279 static void
  280 mc146818_def_setcent(device_t dev, u_int cent)
  281 {
  282         struct mc146818_softc *sc;
  283 
  284         sc = device_get_softc(dev);
  285         (*sc->sc_mcwrite)(dev, MC_CENT, cent);
  286 }
  287 
  288 #undef MC_CENT

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

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sys/dev/mc146818/mc146818.c