1 /* $NetBSD: mm58167.c,v 1.17 2022/09/25 18:43:32 thorpej 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 1.17 2022/09/25 18:43:32 thorpej Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 #include <sys/errno.h> 42 #include <sys/device.h> 43 44 #include <sys/bus.h> 45 #include <dev/clock_subr.h> 46 #include <dev/ic/mm58167var.h> 47 48 static int mm58167_gettime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *); 49 static int mm58167_settime_ymdhms(todr_chip_handle_t, struct clock_ymdhms *); 50 51 /* 52 * To quote SunOS's todreg.h: 53 * "This brain damaged chip insists on keeping the time in 54 * MM/DD HH:MM:SS format, even though it doesn't know about 55 * leap years and Feb. 29, thus making it nearly worthless." 56 */ 57 #define mm58167_read(sc, r) \ 58 bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r) 59 #define mm58167_write(sc, r, v) \ 60 bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v) 61 62 todr_chip_handle_t 63 mm58167_attach(struct mm58167_softc *sc) 64 { 65 struct todr_chip_handle *handle; 66 67 aprint_normal(": mm58167"); 68 69 handle = &sc->_mm58167_todr_handle; 70 memset(handle, 0, sizeof(*handle)); 71 handle->cookie = sc; 72 handle->todr_gettime_ymdhms = mm58167_gettime_ymdhms; 73 handle->todr_settime_ymdhms = mm58167_settime_ymdhms; 74 return handle; 75 } 76 77 /* 78 * Set up the system's time, given a `reasonable' time value. 79 */ 80 int 81 mm58167_gettime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt) 82 { 83 struct mm58167_softc *sc = handle->cookie; 84 struct clock_ymdhms dt_reasonable; 85 struct timeval now; 86 int s; 87 uint8_t byte_value; 88 int leap_year, had_leap_day; 89 90 /* First, read the date out of the chip. */ 91 92 /* No interrupts while we're in the chip. */ 93 s = splhigh(); 94 95 /* Reset the status bit: */ 96 byte_value = mm58167_read(sc, mm58167_status); 97 98 /* 99 * Read the date values until we get a coherent read (one 100 * where the status stays zero, indicating no increment was 101 * rippling through while we were reading). 102 */ 103 do { 104 #define _MM58167_GET(dt_f, mm_f) \ 105 byte_value = mm58167_read(sc, mm_f); \ 106 dt->dt_f = bcdtobin(byte_value) 107 108 _MM58167_GET(dt_mon, mm58167_mon); 109 _MM58167_GET(dt_day, mm58167_day); 110 _MM58167_GET(dt_hour, mm58167_hour); 111 _MM58167_GET(dt_min, mm58167_min); 112 _MM58167_GET(dt_sec, mm58167_sec); 113 #undef _MM58167_GET 114 } while ((mm58167_read(sc, mm58167_status) & 1) == 0); 115 116 splx(s); 117 118 /* Convert the reasonable time into a date: */ 119 getmicrotime(&now); 120 clock_secs_to_ymdhms(now.tv_sec, &dt_reasonable); 121 if (dt_reasonable.dt_year == POSIX_BASE_YEAR) { 122 /* 123 * Not a reasonable year. 124 * Assume called from inittodr(9) on boot and 125 * use file system time set in inittodr(9). 126 */ 127 clock_secs_to_ymdhms(handle->base_time, &dt_reasonable); 128 } 129 130 /* 131 * We need to fake a hardware year. if the hardware MM/DD 132 * HH:MM:SS date is less than the reasonable MM/DD 133 * HH:MM:SS, call it the reasonable year plus one, else call 134 * it the reasonable year. 135 */ 136 if (dt->dt_mon < dt_reasonable.dt_mon || 137 (dt->dt_mon == dt_reasonable.dt_mon && 138 (dt->dt_day < dt_reasonable.dt_day || 139 (dt->dt_day == dt_reasonable.dt_day && 140 (dt->dt_hour < dt_reasonable.dt_hour || 141 (dt->dt_hour == dt_reasonable.dt_hour && 142 (dt->dt_min < dt_reasonable.dt_min || 143 (dt->dt_min == dt_reasonable.dt_min && 144 (dt->dt_sec < dt_reasonable.dt_sec))))))))) { 145 dt->dt_year = dt_reasonable.dt_year + 1; 146 } else { 147 dt->dt_year = dt_reasonable.dt_year; 148 } 149 150 /* 151 * Make a reasonable effort to see if a leap day has passed 152 * that we need to account for. This does the right thing 153 * only when the system was shut down before a leap day, and 154 * it is now after that leap day. It doesn't do the right 155 * thing when a leap day happened while the machine was last 156 * up. When that happens, the hardware clock becomes 157 * instantly wrong forever, until it gets fixed for some 158 * reason. Use NTP to deal. 159 */ 160 161 /* 162 * This may have happened if the hardware says we're into 163 * March in the following year. Check that following year for 164 * a leap day. 165 */ 166 if (dt->dt_year > dt_reasonable.dt_year && 167 dt->dt_mon >= 3) { 168 leap_year = dt->dt_year; 169 } 170 171 /* 172 * This may have happened if the hardware says we're in the 173 * following year, and the system was shut down before March 174 * the previous year. check that previous year for a leap 175 * day. 176 */ 177 else if (dt->dt_year > dt_reasonable.dt_year && 178 dt_reasonable.dt_mon < 3) { 179 leap_year = dt_reasonable.dt_year; 180 } 181 182 /* 183 * This may have happened if the hardware says we're in the 184 * same year, but we weren't to March before, and we're in or 185 * past March now. Check this year for a leap day. 186 */ 187 else if (dt->dt_year == dt_reasonable.dt_year 188 && dt_reasonable.dt_mon < 3 189 && dt->dt_mon >= 3) { 190 leap_year = dt_reasonable.dt_year; 191 } 192 193 /* 194 * Otherwise, no leap year to check. 195 */ 196 else { 197 leap_year = 0; 198 } 199 200 /* Do the real leap day check. */ 201 had_leap_day = 0; 202 if (leap_year > 0) { 203 if ((leap_year & 3) == 0) { 204 had_leap_day = 1; 205 if ((leap_year % 100) == 0) { 206 had_leap_day = 0; 207 if ((leap_year % 400) == 0) 208 had_leap_day = 1; 209 } 210 } 211 } 212 213 /* 214 * If we had a leap day, adjust the value we will return, and 215 * also update the hardware clock. 216 */ 217 /* 218 * XXX - Since this update just writes back a corrected 219 * version of what we read out above, we lose whatever 220 * amount of time the clock has advanced since that read. 221 * Use NTP to deal. 222 */ 223 if (had_leap_day) { 224 mm58167_settime_ymdhms(handle, dt); 225 } 226 227 return 0; 228 } 229 230 int 231 mm58167_settime_ymdhms(todr_chip_handle_t handle, struct clock_ymdhms *dt) 232 { 233 struct mm58167_softc *sc = handle->cookie; 234 int s; 235 uint8_t byte_value; 236 237 /* No interrupts while we're in the chip. */ 238 s = splhigh(); 239 240 /* 241 * Issue a GO command to reset everything less significant 242 * than the minutes to zero. 243 */ 244 mm58167_write(sc, mm58167_go, 0xFF); 245 246 /* Load everything. */ 247 #define _MM58167_PUT(dt_f, mm_f) \ 248 byte_value = bintobcd(dt->dt_f); \ 249 mm58167_write(sc, mm_f, byte_value) 250 251 _MM58167_PUT(dt_mon, mm58167_mon); 252 _MM58167_PUT(dt_day, mm58167_day); 253 _MM58167_PUT(dt_hour, mm58167_hour); 254 _MM58167_PUT(dt_min, mm58167_min); 255 _MM58167_PUT(dt_sec, mm58167_sec); 256 #undef _MM58167_PUT 257 258 splx(s); 259 return 0; 260 } 261