1 /* $NetBSD: mm58167.c,v 1.10 2008/04/28 20:23:50 martin Exp $ */ 2 3 /* 4 * Copyright (c) 2001 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Matthew Fredette. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * National Semiconductor MM58167 time-of-day chip subroutines. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: mm58167.c,v 1.10 2008/04/28 20:23:50 martin Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/malloc.h> 41 #include <sys/systm.h> 42 #include <sys/errno.h> 43 #include <sys/device.h> 44 45 #include <sys/bus.h> 46 #include <dev/clock_subr.h> 47 #include <dev/ic/mm58167var.h> 48 49 int mm58167_gettime(todr_chip_handle_t, volatile struct timeval *); 50 int mm58167_settime(todr_chip_handle_t, volatile struct timeval *); 51 52 /* 53 * To quote SunOS's todreg.h: 54 * "This brain damaged chip insists on keeping the time in 55 * MM/DD HH:MM:SS format, even though it doesn't know about 56 * leap years and Feb. 29, thus making it nearly worthless." 57 */ 58 #define mm58167_read(sc, r) bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r) 59 #define mm58167_write(sc, r, v) bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v) 60 61 todr_chip_handle_t 62 mm58167_attach(sc) 63 struct mm58167_softc *sc; 64 { 65 struct todr_chip_handle *handle; 66 67 printf(": mm58167"); 68 69 handle = &sc->_mm58167_todr_handle; 70 memset(handle, 0, sizeof(handle)); 71 handle->cookie = sc; 72 handle->todr_gettime = mm58167_gettime; 73 handle->todr_settime = mm58167_settime; 74 return (handle); 75 } 76 77 /* 78 * Set up the system's time, given a `reasonable' time value. 79 */ 80 int 81 mm58167_gettime(handle, tv) 82 todr_chip_handle_t handle; 83 volatile struct timeval *tv; 84 { 85 struct mm58167_softc *sc = handle->cookie; 86 struct clock_ymdhms dt_hardware; 87 struct clock_ymdhms dt_reasonable; 88 int s; 89 u_int8_t byte_value; 90 int leap_year, had_leap_day; 91 92 /* First, read the date out of the chip. */ 93 94 /* No interrupts while we're in the chip. */ 95 s = splhigh(); 96 97 /* Reset the status bit: */ 98 byte_value = mm58167_read(sc, mm58167_status); 99 100 /* 101 * Read the date values until we get a coherent read (one 102 * where the status stays zero, indicating no increment was 103 * rippling through while we were reading). 104 */ 105 do { 106 #define _MM58167_GET(dt_f, mm_f) byte_value = mm58167_read(sc, mm_f); dt_hardware.dt_f = FROMBCD(byte_value) 107 _MM58167_GET(dt_mon, mm58167_mon); 108 _MM58167_GET(dt_day, mm58167_day); 109 _MM58167_GET(dt_hour, mm58167_hour); 110 _MM58167_GET(dt_min, mm58167_min); 111 _MM58167_GET(dt_sec, mm58167_sec); 112 #undef _MM58167_GET 113 } while ((mm58167_read(sc, mm58167_status) & 1) == 0); 114 115 splx(s); 116 117 /* Convert the reasonable time into a date: */ 118 clock_secs_to_ymdhms(tv->tv_sec, &dt_reasonable); 119 120 /* 121 * We need to fake a hardware year. if the hardware MM/DD 122 * HH:MM:SS date is less than the reasonable MM/DD 123 * HH:MM:SS, call it the reasonable year plus one, else call 124 * it the reasonable year. 125 */ 126 if (dt_hardware.dt_mon < dt_reasonable.dt_mon || 127 (dt_hardware.dt_mon == dt_reasonable.dt_mon && 128 (dt_hardware.dt_day < dt_reasonable.dt_day || 129 (dt_hardware.dt_day == dt_reasonable.dt_day && 130 (dt_hardware.dt_hour < dt_reasonable.dt_hour || 131 (dt_hardware.dt_hour == dt_reasonable.dt_hour && 132 (dt_hardware.dt_min < dt_reasonable.dt_min || 133 (dt_hardware.dt_min == dt_reasonable.dt_min && 134 (dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) { 135 dt_hardware.dt_year = dt_reasonable.dt_year + 1; 136 } else { 137 dt_hardware.dt_year = dt_reasonable.dt_year; 138 } 139 140 /* convert the hardware date into a time: */ 141 tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware); 142 tv->tv_usec = 0; 143 144 /* 145 * Make a reasonable effort to see if a leap day has passed 146 * that we need to account for. This does the right thing 147 * only when the system was shut down before a leap day, and 148 * it is now after that leap day. It doesn't do the right 149 * thing when a leap day happened while the machine was last 150 * up. When that happens, the hardware clock becomes 151 * instantly wrong forever, until it gets fixed for some 152 * reason. Use NTP to deal. 153 */ 154 155 /* 156 * This may have happened if the hardware says we're into 157 * March in the following year. Check that following year for 158 * a leap day. 159 */ 160 if (dt_hardware.dt_year > dt_reasonable.dt_year && 161 dt_hardware.dt_mon >= 3) { 162 leap_year = dt_hardware.dt_year; 163 } 164 165 /* 166 * This may have happened if the hardware says we're in the 167 * following year, and the system was shut down before March 168 * the previous year. check that previous year for a leap 169 * day. 170 */ 171 else if (dt_hardware.dt_year > dt_reasonable.dt_year && 172 dt_reasonable.dt_mon < 3) { 173 leap_year = dt_reasonable.dt_year; 174 } 175 176 /* 177 * This may have happened if the hardware says we're in the 178 * same year, but we weren't to March before, and we're in or 179 * past March now. Check this year for a leap day. 180 */ 181 else if (dt_hardware.dt_year == dt_reasonable.dt_year 182 && dt_reasonable.dt_mon < 3 183 && dt_hardware.dt_mon >= 3) { 184 leap_year = dt_reasonable.dt_year; 185 } 186 187 /* 188 * Otherwise, no leap year to check. 189 */ 190 else { 191 leap_year = 0; 192 } 193 194 /* Do the real leap day check. */ 195 had_leap_day = 0; 196 if (leap_year > 0) { 197 if ((leap_year & 3) == 0) { 198 had_leap_day = 1; 199 if ((leap_year % 100) == 0) { 200 had_leap_day = 0; 201 if ((leap_year % 400) == 0) 202 had_leap_day = 1; 203 } 204 } 205 } 206 207 /* 208 * If we had a leap day, adjust the value we will return, and 209 * also update the hardware clock. 210 */ 211 /* 212 * XXX - Since this update just writes back a corrected 213 * version of what we read out above, we lose whatever 214 * amount of time the clock has advanced since that read. 215 * Use NTP to deal. 216 */ 217 if (had_leap_day) { 218 tv->tv_sec += SECDAY; 219 todr_settime(handle, tv); 220 } 221 222 return (0); 223 } 224 225 int 226 mm58167_settime(handle, tv) 227 todr_chip_handle_t handle; 228 volatile struct timeval *tv; 229 { 230 struct mm58167_softc *sc = handle->cookie; 231 struct clock_ymdhms dt_hardware; 232 int s; 233 u_int8_t byte_value; 234 235 /* Convert the seconds into ymdhms. */ 236 clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware); 237 238 /* No interrupts while we're in the chip. */ 239 s = splhigh(); 240 241 /* 242 * Issue a GO command to reset everything less significant 243 * than the minutes to zero. 244 */ 245 mm58167_write(sc, mm58167_go, 0xFF); 246 247 /* Load everything. */ 248 #define _MM58167_PUT(dt_f, mm_f) byte_value = TOBCD(dt_hardware.dt_f); mm58167_write(sc, mm_f, byte_value) 249 _MM58167_PUT(dt_mon, mm58167_mon); 250 _MM58167_PUT(dt_day, mm58167_day); 251 _MM58167_PUT(dt_hour, mm58167_hour); 252 _MM58167_PUT(dt_min, mm58167_min); 253 _MM58167_PUT(dt_sec, mm58167_sec); 254 #undef _MM58167_PUT 255 256 splx(s); 257 return (0); 258 } 259