1 /* 2 * Copyright (c) 1988 University of Utah. 3 * Copyright (c) 1992, 1993 4 * The Regents of the University of California. 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 8.1 (Berkeley) 06/10/93 15 */ 16 17 #include <sys/param.h> 18 #include <sys/kernel.h> 19 20 #include <machine/machConst.h> 21 #include <pmax/pmax/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 volatile struct chiptime *Mach_clock_addr; 37 38 /* 39 * Start the real-time and statistics clocks. Leave stathz 0 since there 40 * are no other timers available. 41 */ 42 cpu_initclocks() 43 { 44 register volatile struct chiptime *c; 45 extern int tickadj; 46 47 tick = 15625; /* number of micro-seconds between interrupts */ 48 hz = 1000000 / 15625; /* 64 Hz */ 49 tickadj = 240000 / (60000000 / 15625); 50 c = Mach_clock_addr; 51 c->rega = REGA_TIME_BASE | SELECTED_RATE; 52 c->regb = REGB_PER_INT_ENA | REGB_DATA_MODE | REGB_HOURS_FORMAT; 53 } 54 55 /* 56 * We assume newhz is either stathz or profhz, and that neither will 57 * change after being set up above. Could recalculate intervals here 58 * but that would be a drag. 59 */ 60 void 61 setstatclockrate(newhz) 62 int newhz; 63 { 64 } 65 66 /* 67 * This code is defunct after 2099. 68 * Will Unix still be here then?? 69 */ 70 static short dayyr[12] = { 71 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 72 }; 73 74 /* 75 * Initialze the time of day register, based on the time base which is, e.g. 76 * from a filesystem. Base provides the time to within six months, 77 * and the time of year clock (if any) provides the rest. 78 */ 79 void 80 inittodr(base) 81 time_t base; 82 { 83 register volatile struct chiptime *c; 84 register int days, yr; 85 int sec, min, hour, day, mon, year; 86 long deltat; 87 int badbase, s; 88 89 if (base < 5*SECYR) { 90 printf("WARNING: preposterous time in file system"); 91 /* read the system clock anyway */ 92 base = 6*SECYR + 186*SECDAY + SECDAY/2; 93 badbase = 1; 94 } else 95 badbase = 0; 96 97 c = Mach_clock_addr; 98 /* don't read clock registers while they are being updated */ 99 s = splclock(); 100 while ((c->rega & REGA_UIP) == 1) 101 ; 102 sec = c->sec; 103 min = c->min; 104 hour = c->hour; 105 day = c->day; 106 mon = c->mon; 107 year = c->year + 20; /* must be multiple of 4 because chip knows leap */ 108 splx(s); 109 110 /* simple sanity checks */ 111 if (year < 70 || mon < 1 || mon > 12 || day < 1 || day > 31 || 112 hour > 23 || min > 59 || sec > 59) { 113 /* 114 * Believe the time in the file system for lack of 115 * anything better, resetting the TODR. 116 */ 117 time.tv_sec = base; 118 if (!badbase) { 119 printf("WARNING: preposterous clock chip time\n"); 120 resettodr(); 121 } 122 goto bad; 123 } 124 days = 0; 125 for (yr = 70; yr < year; yr++) 126 days += LEAPYEAR(yr) ? 366 : 365; 127 days += dayyr[mon - 1] + day - 1; 128 if (LEAPYEAR(yr) && mon > 2) 129 days++; 130 /* now have days since Jan 1, 1970; the rest is easy... */ 131 time.tv_sec = days * SECDAY + hour * 3600 + min * 60 + sec; 132 133 if (!badbase) { 134 /* 135 * See if we gained/lost two or more days; 136 * if so, assume something is amiss. 137 */ 138 deltat = time.tv_sec - base; 139 if (deltat < 0) 140 deltat = -deltat; 141 if (deltat < 2 * SECDAY) 142 return; 143 printf("WARNING: clock %s %d days", 144 time.tv_sec < base ? "lost" : "gained", deltat / SECDAY); 145 } 146 bad: 147 printf(" -- CHECK AND RESET THE DATE!\n"); 148 } 149 150 /* 151 * Reset the TODR based on the time value; used when the TODR 152 * has a preposterous value and also when the time is reset 153 * by the stime system call. Also called when the TODR goes past 154 * TODRZERO + 100*(SECYEAR+2*SECDAY) (e.g. on Jan 2 just after midnight) 155 * to wrap the TODR around. 156 */ 157 resettodr() 158 { 159 register volatile struct chiptime *c; 160 register int t, t2; 161 int sec, min, hour, day, mon, year; 162 int s; 163 164 /* compute the year */ 165 t2 = time.tv_sec / SECDAY; 166 year = 69; 167 while (t2 >= 0) { /* whittle off years */ 168 t = t2; 169 year++; 170 t2 -= LEAPYEAR(year) ? 366 : 365; 171 } 172 173 /* t = month + day; separate */ 174 t2 = LEAPYEAR(year); 175 for (mon = 1; mon < 12; mon++) 176 if (t < dayyr[mon] + (t2 && mon > 1)) 177 break; 178 179 day = t - dayyr[mon - 1] + 1; 180 if (t2 && mon > 2) 181 day--; 182 183 /* the rest is easy */ 184 t = time.tv_sec % SECDAY; 185 hour = t / 3600; 186 t %= 3600; 187 min = t / 60; 188 sec = t % 60; 189 190 c = Mach_clock_addr; 191 s = splclock(); 192 t = c->regb; 193 c->regb = t | REGB_SET_TIME; 194 MachEmptyWriteBuffer(); 195 c->sec = sec; 196 c->min = min; 197 c->hour = hour; 198 c->day = day; 199 c->mon = mon; 200 c->year = year - 20; /* must be multiple of 4 because chip knows leap */ 201 c->regb = t; 202 MachEmptyWriteBuffer(); 203 splx(s); 204 } 205