sys/arch/dreamcast/dev/g2/g2rtc.c

   1 /* $NetBSD: g2rtc.c,v 1.3 2008/04/28 20:23:16 martin Exp $ */
   2
   3 /*-
   4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  26  * POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include <sys/cdefs.h>
  30 __KERNEL_RCSID(0, "$NetBSD: g2rtc.c,v 1.3 2008/04/28 20:23:16 martin Exp $");
  31
  32 #include <sys/param.h>
  33 #include <sys/systm.h>
  34 #include <sys/device.h>
  35
  36 #include <dev/clock_subr.h>
  37
  38 #include <machine/bus.h>
  39 #include <dreamcast/dev/g2/g2busvar.h>
  40
  41
  42 #define G2RTC_REG_BASE  0x00710000
  43 #define G2RTC_REG_SIZE  12
  44
  45 /* Offset by 20 years, 5 of them are leap */
  46 #define G2RTC_OFFSET    (20 * SECYR + 5 * SECDAY)
  47
  48 struct g2rtc_softc {
  49         struct device sc_dev;
  50
  51         bus_space_tag_t sc_bt;
  52         bus_space_handle_t sc_bh;
  53 };
  54
  55 /* autoconf glue */
  56 static int g2rtc_match(struct device *, struct cfdata *, void *);
  57 static void g2rtc_attach(struct device *, struct device *, void *);
  58
  59 CFATTACH_DECL(g2rtc, sizeof(struct g2rtc_softc),
  60               g2rtc_match, g2rtc_attach, NULL, NULL);
  61
  62
  63 /* todr(9) methods */
  64 static int g2rtc_todr_gettime(todr_chip_handle_t, struct timeval *);
  65 static int g2rtc_todr_settime(todr_chip_handle_t, struct timeval *);
  66
  67 static struct todr_chip_handle g2rtc_todr_handle = {
  68         .cookie       = NULL,   /* set on attach */
  69         .todr_gettime = g2rtc_todr_gettime,
  70         .todr_settime = g2rtc_todr_settime,
  71 };
  72
  73
  74 static inline uint32_t g2rtc_read(bus_space_tag_t, bus_space_handle_t);
  75
  76
  77 static int
  78 g2rtc_match(struct device *parent, struct cfdata *cf, void *aux)
  79 {
  80         static int g2rtc_matched = 0;
  81
  82         if (g2rtc_matched)
  83                 return 0;
  84
  85         g2rtc_matched = 1;
  86         return 1;
  87 }
  88
  89
  90 static void
  91 g2rtc_attach(struct device *parent, struct device *self, void *aux)
  92 {
  93         struct g2rtc_softc *sc = (void *)self;
  94         struct g2bus_attach_args *ga = aux;
  95
  96         sc->sc_bt = ga->ga_memt;
  97         if (bus_space_map(sc->sc_bt, G2RTC_REG_BASE, G2RTC_REG_SIZE, 0,
  98                           &sc->sc_bh) != 0)
  99         {
 100                 printf(": unable to map registers\n");
 101                 return;
 102         }
 103         printf(": time-of-day clock\n");
 104
 105         g2rtc_todr_handle.cookie = sc;
 106         todr_attach(&g2rtc_todr_handle);
 107 }
 108
 109
 110 static inline uint32_t
 111 g2rtc_read(bus_space_tag_t bt, bus_space_handle_t bh)
 112 {
 113
 114         return ((bus_space_read_4(bt, bh, 0) & 0xffff) << 16)
 115                 | (bus_space_read_4(bt, bh, 4) & 0xffff);
 116 }
 117
 118
 119 /*
 120  * Get time-of-day and convert to `struct timeval'.
 121  * Return 0 on success; an error number otherwise.
 122  */
 123 static int
 124 g2rtc_todr_gettime(todr_chip_handle_t handle, struct timeval *tv)
 125 {
 126         struct g2rtc_softc *sc = handle->cookie;
 127         uint32_t new, old;
 128         int i;
 129
 130         for (old = 0;;) {
 131                 for (i = 0; i < 3; i++) {
 132                         new = g2rtc_read(sc->sc_bt, sc->sc_bh);
 133                         if (new != old)
 134                                 break;
 135                 }
 136                 if (i < 3)
 137                         old = new;
 138                 else
 139                         break;
 140         }
 141
 142         tv->tv_sec = new - G2RTC_OFFSET;
 143         tv->tv_usec = 0;
 144
 145         return 0;
 146 }
 147
 148
 149 /*
 150  * Set the time-of-day clock based on the value of the `struct timeval' arg.
 151  * Return 0 on success; an error number otherwise.
 152  */
 153 static int
 154 g2rtc_todr_settime(todr_chip_handle_t handle, struct timeval *tv)
 155 {
 156         struct g2rtc_softc *sc = handle->cookie;
 157         uint32_t secs;
 158         int i, retry;
 159
 160         secs = (uint32_t)tv->tv_sec + G2RTC_OFFSET;
 161
 162         for (retry = 0; retry < 5; retry++) {
 163
 164                 /* Don't change the order */
 165                 bus_space_write_4(sc->sc_bt, sc->sc_bh, 8, 1);
 166                 bus_space_write_4(sc->sc_bt, sc->sc_bh, 4, secs & 0xffff);
 167                 bus_space_write_4(sc->sc_bt, sc->sc_bh, 0, secs >> 16);
 168
 169                 /* verify */
 170                 for (i = 0; i < 3; i++)
 171                         if (g2rtc_read(sc->sc_bt, sc->sc_bh) == secs)
 172                                 return 0; /* ok */
 173         }
 174
 175         return EIO;
 176
 177 }