mm58167.c revision 1.9
1 /* $NetBSD: mm58167.c,v 1.9 2007/10/19 11:59:57 ad 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 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * National Semiconductor MM58167 time-of-day chip subroutines. 41 */ 42 43 #include <sys/cdefs.h> 44 __KERNEL_RCSID(0, "$NetBSD: mm58167.c,v 1.9 2007/10/19 11:59:57 ad Exp $"); 45 46 #include <sys/param.h> 47 #include <sys/malloc.h> 48 #include <sys/systm.h> 49 #include <sys/errno.h> 50 #include <sys/device.h> 51 52 #include <sys/bus.h> 53 #include <dev/clock_subr.h> 54 #include <dev/ic/mm58167var.h> 55 56 int mm58167_gettime(todr_chip_handle_t, volatile struct timeval *); 57 int mm58167_settime(todr_chip_handle_t, volatile struct timeval *); 58 59 /* 60 * To quote SunOS's todreg.h: 61 * "This brain damaged chip insists on keeping the time in 62 * MM/DD HH:MM:SS format, even though it doesn't know about 63 * leap years and Feb. 29, thus making it nearly worthless." 64 */ 65 #define mm58167_read(sc, r) bus_space_read_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r) 66 #define mm58167_write(sc, r, v) bus_space_write_1(sc->mm58167_regt, sc->mm58167_regh, sc-> r, v) 67 68 todr_chip_handle_t 69 mm58167_attach(sc) 70 struct mm58167_softc *sc; 71 { 72 struct todr_chip_handle *handle; 73 74 printf(": mm58167"); 75 76 handle = &sc->_mm58167_todr_handle; 77 memset(handle, 0, sizeof(handle)); 78 handle->cookie = sc; 79 handle->todr_gettime = mm58167_gettime; 80 handle->todr_settime = mm58167_settime; 81 return (handle); 82 } 83 84 /* 85 * Set up the system's time, given a `reasonable' time value. 86 */ 87 int 88 mm58167_gettime(handle, tv) 89 todr_chip_handle_t handle; 90 volatile struct timeval *tv; 91 { 92 struct mm58167_softc *sc = handle->cookie; 93 struct clock_ymdhms dt_hardware; 94 struct clock_ymdhms dt_reasonable; 95 int s; 96 u_int8_t byte_value; 97 int leap_year, had_leap_day; 98 99 /* First, read the date out of the chip. */ 100 101 /* No interrupts while we're in the chip. */ 102 s = splhigh(); 103 104 /* Reset the status bit: */ 105 byte_value = mm58167_read(sc, mm58167_status); 106 107 /* 108 * Read the date values until we get a coherent read (one 109 * where the status stays zero, indicating no increment was 110 * rippling through while we were reading). 111 */ 112 do { 113 #define _MM58167_GET(dt_f, mm_f) byte_value = mm58167_read(sc, mm_f); dt_hardware.dt_f = FROMBCD(byte_value) 114 _MM58167_GET(dt_mon, mm58167_mon); 115 _MM58167_GET(dt_day, mm58167_day); 116 _MM58167_GET(dt_hour, mm58167_hour); 117 _MM58167_GET(dt_min, mm58167_min); 118 _MM58167_GET(dt_sec, mm58167_sec); 119 #undef _MM58167_GET 120 } while ((mm58167_read(sc, mm58167_status) & 1) == 0); 121 122 splx(s); 123 124 /* Convert the reasonable time into a date: */ 125 clock_secs_to_ymdhms(tv->tv_sec, &dt_reasonable); 126 127 /* 128 * We need to fake a hardware year. if the hardware MM/DD 129 * HH:MM:SS date is less than the reasonable MM/DD 130 * HH:MM:SS, call it the reasonable year plus one, else call 131 * it the reasonable year. 132 */ 133 if (dt_hardware.dt_mon < dt_reasonable.dt_mon || 134 (dt_hardware.dt_mon == dt_reasonable.dt_mon && 135 (dt_hardware.dt_day < dt_reasonable.dt_day || 136 (dt_hardware.dt_day == dt_reasonable.dt_day && 137 (dt_hardware.dt_hour < dt_reasonable.dt_hour || 138 (dt_hardware.dt_hour == dt_reasonable.dt_hour && 139 (dt_hardware.dt_min < dt_reasonable.dt_min || 140 (dt_hardware.dt_min == dt_reasonable.dt_min && 141 (dt_hardware.dt_sec < dt_reasonable.dt_sec))))))))) { 142 dt_hardware.dt_year = dt_reasonable.dt_year + 1; 143 } else { 144 dt_hardware.dt_year = dt_reasonable.dt_year; 145 } 146 147 /* convert the hardware date into a time: */ 148 tv->tv_sec = clock_ymdhms_to_secs(&dt_hardware); 149 tv->tv_usec = 0; 150 151 /* 152 * Make a reasonable effort to see if a leap day has passed 153 * that we need to account for. This does the right thing 154 * only when the system was shut down before a leap day, and 155 * it is now after that leap day. It doesn't do the right 156 * thing when a leap day happened while the machine was last 157 * up. When that happens, the hardware clock becomes 158 * instantly wrong forever, until it gets fixed for some 159 * reason. Use NTP to deal. 160 */ 161 162 /* 163 * This may have happened if the hardware says we're into 164 * March in the following year. Check that following year for 165 * a leap day. 166 */ 167 if (dt_hardware.dt_year > dt_reasonable.dt_year && 168 dt_hardware.dt_mon >= 3) { 169 leap_year = dt_hardware.dt_year; 170 } 171 172 /* 173 * This may have happened if the hardware says we're in the 174 * following year, and the system was shut down before March 175 * the previous year. check that previous year for a leap 176 * day. 177 */ 178 else if (dt_hardware.dt_year > dt_reasonable.dt_year && 179 dt_reasonable.dt_mon < 3) { 180 leap_year = dt_reasonable.dt_year; 181 } 182 183 /* 184 * This may have happened if the hardware says we're in the 185 * same year, but we weren't to March before, and we're in or 186 * past March now. Check this year for a leap day. 187 */ 188 else if (dt_hardware.dt_year == dt_reasonable.dt_year 189 && dt_reasonable.dt_mon < 3 190 && dt_hardware.dt_mon >= 3) { 191 leap_year = dt_reasonable.dt_year; 192 } 193 194 /* 195 * Otherwise, no leap year to check. 196 */ 197 else { 198 leap_year = 0; 199 } 200 201 /* Do the real leap day check. */ 202 had_leap_day = 0; 203 if (leap_year > 0) { 204 if ((leap_year & 3) == 0) { 205 had_leap_day = 1; 206 if ((leap_year % 100) == 0) { 207 had_leap_day = 0; 208 if ((leap_year % 400) == 0) 209 had_leap_day = 1; 210 } 211 } 212 } 213 214 /* 215 * If we had a leap day, adjust the value we will return, and 216 * also update the hardware clock. 217 */ 218 /* 219 * XXX - Since this update just writes back a corrected 220 * version of what we read out above, we lose whatever 221 * amount of time the clock has advanced since that read. 222 * Use NTP to deal. 223 */ 224 if (had_leap_day) { 225 tv->tv_sec += SECDAY; 226 todr_settime(handle, tv); 227 } 228 229 return (0); 230 } 231 232 int 233 mm58167_settime(handle, tv) 234 todr_chip_handle_t handle; 235 volatile struct timeval *tv; 236 { 237 struct mm58167_softc *sc = handle->cookie; 238 struct clock_ymdhms dt_hardware; 239 int s; 240 u_int8_t byte_value; 241 242 /* Convert the seconds into ymdhms. */ 243 clock_secs_to_ymdhms(tv->tv_sec, &dt_hardware); 244 245 /* No interrupts while we're in the chip. */ 246 s = splhigh(); 247 248 /* 249 * Issue a GO command to reset everything less significant 250 * than the minutes to zero. 251 */ 252 mm58167_write(sc, mm58167_go, 0xFF); 253 254 /* Load everything. */ 255 #define _MM58167_PUT(dt_f, mm_f) byte_value = TOBCD(dt_hardware.dt_f); mm58167_write(sc, mm_f, byte_value) 256 _MM58167_PUT(dt_mon, mm58167_mon); 257 _MM58167_PUT(dt_day, mm58167_day); 258 _MM58167_PUT(dt_hour, mm58167_hour); 259 _MM58167_PUT(dt_min, mm58167_min); 260 _MM58167_PUT(dt_sec, mm58167_sec); 261 #undef _MM58167_PUT 262 263 splx(s); 264 return (0); 265 } 266
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