1 /* 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1992 The Regents of the University of California. 4 * All rights reserved. 5 * 6 * This code is derived from software contributed to Berkeley by 7 * the Systems Programming Group of the University of Utah Computer 8 * Science Department and Ralph Campbell. 9 * 10 * %sccs.include.redist.c% 11 * 12 * from: Utah $Hdr: clock.c 1.18 91/01/21$ 13 * 14 * @(#)clock.c 7.1 (Berkeley) 01/07/92 15 */ 16 17 #include "param.h" 18 #include "kernel.h" 19 20 #include "../include/machConst.h" 21 #include "clockreg.h" 22 23 /* 24 * Machine-dependent clock routines. 25 * 26 * Startrtclock restarts the real-time clock, which provides 27 * hardclock interrupts to kern_clock.c. 28 * 29 * Inittodr initializes the time of day hardware which provides 30 * date functions. Its primary function is to use some file 31 * system information in case the hardare clock lost state. 32 * 33 * Resettodr restores the time of day hardware after a time change. 34 */ 35 36 /* 37 * Start the real-time clock. 38 */ 39 startrtclock() 40 { 41 register volatile struct chiptime *c; 42 extern int tickadj; 43 44 tick = 15625; /* number of micro-seconds between interrupts */ 45 hz = 1000000 / 15625; /* about 64 */ 46 tickadj = 240000 / (60000000 / 15625); 47 c = (volatile struct chiptime *)MACH_CLOCK_ADDR; 48 c->rega = REGA_TIME_BASE | SELECTED_RATE; 49 c->regb = REGB_PER_INT_ENA | REGB_DATA_MODE | REGB_HOURS_FORMAT; 50 } 51 52 /* 53 * This code is defunct after 2099. 54 * Will Unix still be here then?? 55 */ 56 static short dayyr[12] = { 57 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 58 }; 59 60 /* 61 * Initialze the time of day register, based on the time base which is, e.g. 62 * from a filesystem. Base provides the time to within six months, 63 * and the time of year clock (if any) provides the rest. 64 */ 65 inittodr(base) 66 time_t base; 67 { 68 register volatile struct chiptime *c; 69 register int days, yr; 70 int sec, min, hour, day, mon, year; 71 long deltat, badbase = 0; 72 int s; 73 74 if (base < 5*SECYR) { 75 printf("WARNING: preposterous time in file system\n"); 76 /* read the system clock anyway */ 77 base = 6*SECYR + 186*SECDAY + SECDAY/2; 78 badbase = 1; 79 } 80 81 s = splclock(); 82 c = (volatile struct chiptime *)MACH_CLOCK_ADDR; 83 /* don't read clock registers while they are being updated */ 84 while ((c->rega & REGA_UIP) == 1) 85 ; 86 sec = c->sec; 87 min = c->min; 88 hour = c->hour; 89 day = c->day; 90 mon = c->mon; 91 year = c->year + 19; 92 splx(s); 93 /* simple sanity checks */ 94 if (year < 70 || mon < 1 || mon > 12 || day < 1 || day > 31 || 95 hour > 23 || min > 59 || sec > 59) { 96 printf("WARNING: preposterous clock chip time"); 97 /* 98 * Believe the time in the file system for lack of 99 * anything better, resetting the TODR. 100 */ 101 time.tv_sec = base; 102 if (!badbase) 103 resettodr(); 104 return (0); 105 } 106 days = 0; 107 for (yr = 70; yr < year; yr++) 108 days += LEAPYEAR(yr) ? 366 : 365; 109 days += dayyr[mon - 1] + day - 1; 110 if (LEAPYEAR(yr) && mon > 2) 111 days++; 112 /* now have days since Jan 1, 1970; the rest is easy... */ 113 time.tv_sec = days * SECDAY + hour * 3600 + min * 60 + sec; 114 115 if (!badbase) { 116 /* 117 * See if we gained/lost two or more days; 118 * if so, assume something is amiss. 119 */ 120 deltat = time.tv_sec - base; 121 if (deltat < 0) 122 deltat = -deltat; 123 if (deltat < 2 * SECDAY) 124 return; 125 printf("WARNING: clock %s %d days", 126 time.tv_sec < base ? "lost" : "gained", deltat / SECDAY); 127 } 128 printf(" -- CHECK AND RESET THE DATE!\n"); 129 } 130 131 /* 132 * Reset the TODR based on the time value; used when the TODR 133 * has a preposterous value and also when the time is reset 134 * by the stime system call. Also called when the TODR goes past 135 * TODRZERO + 100*(SECYEAR+2*SECDAY) (e.g. on Jan 2 just after midnight) 136 * to wrap the TODR around. 137 */ 138 resettodr() 139 { 140 register volatile struct chiptime *c; 141 register int t, t2, t3; 142 143 /* compute the year */ 144 t2 = time.tv_sec / SECDAY; 145 t = 69; 146 while (t2 >= 0) { /* whittle off years */ 147 t3 = t2; 148 t++; 149 t2 -= LEAPYEAR(t) ? 366 : 365; 150 } 151 c = (volatile struct chiptime *)MACH_CLOCK_ADDR; 152 c->regb |= REGB_SET_TIME; 153 c->year = t - 19; 154 155 /* t3 = month + day; separate */ 156 t = LEAPYEAR(t); 157 for (t2 = 1; t2 < 12; t2++) 158 if (t3 < dayyr[t2] + (t && t2 > 1)) 159 break; 160 161 /* t2 is month */ 162 c->mon = t2; 163 t3 = t3 - dayyr[t2 - 1] + 1; 164 if (t && t2 > 2) 165 t3--; 166 c->day = t3; 167 168 /* the rest is easy */ 169 t = time.tv_sec % SECDAY; 170 c->hour = t / 3600; 171 t %= 3600; 172 c->min = t / 60; 173 c->sec = t % 60; 174 c->regb &= ~REGB_SET_TIME; 175 } 176