/* $Id: time.c,v 1.29 1997/04/18 09:48:44 davem Exp $ * linux/arch/sparc/kernel/time.c * * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu) * * This file handles the Sparc specific time handling details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include enum sparc_clock_type sp_clock_typ; struct mostek48t02 *mstk48t02_regs = 0; struct mostek48t08 *mstk48t08_regs = 0; static int set_rtc_mmss(unsigned long); __volatile__ unsigned int *master_l10_counter; __volatile__ unsigned int *master_l10_limit; /* * timer_interrupt() needs to keep up the real-time clock, * as well as call the "do_timer()" routine every clocktick */ void timer_interrupt(int irq, void *dev_id, struct pt_regs * regs) { /* last time the cmos clock got updated */ static long last_rtc_update=0; clear_clock_irq(); do_timer(regs); /* Determine when to update the Mostek clock. */ if (time_state != TIME_BAD && xtime.tv_sec > last_rtc_update + 660 && xtime.tv_usec > 500000 - (tick >> 1) && xtime.tv_usec < 500000 + (tick >> 1)) if (set_rtc_mmss(xtime.tv_sec) == 0) last_rtc_update = xtime.tv_sec; else last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */ } /* Converts Gregorian date to seconds since 1970-01-01 00:00:00. * Assumes input in normal date format, i.e. 1980-12-31 23:59:59 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59. * * [For the Julian calendar (which was used in Russia before 1917, * Britain & colonies before 1752, anywhere else before 1582, * and is still in use by some communities) leave out the * -year/100+year/400 terms, and add 10.] * * This algorithm was first published by Gauss (I think). * * WARNING: this function will overflow on 2106-02-07 06:28:16 on * machines were long is 32-bit! (However, as time_t is signed, we * will already get problems at other places on 2038-01-19 03:14:08) */ static inline unsigned long mktime(unsigned int year, unsigned int mon, unsigned int day, unsigned int hour, unsigned int min, unsigned int sec) { if (0 >= (int) (mon -= 2)) { /* 1..12 -> 11,12,1..10 */ mon += 12; /* Puts Feb last since it has leap day */ year -= 1; } return ((( (unsigned long)(year/4 - year/100 + year/400 + 367*mon/12 + day) + year*365 - 719499 )*24 + hour /* now have hours */ )*60 + min /* now have minutes */ )*60 + sec; /* finally seconds */ } /* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */ static void kick_start_clock(void) { register struct mostek48t02 *regs = mstk48t02_regs; unsigned char sec; int i, count; prom_printf("CLOCK: Clock was stopped. Kick start "); /* Turn on the kick start bit to start the oscillator. */ regs->creg |= MSTK_CREG_WRITE; regs->sec &= ~MSTK_STOP; regs->hour |= MSTK_KICK_START; regs->creg &= ~MSTK_CREG_WRITE; /* Delay to allow the clock oscillator to start. */ sec = MSTK_REG_SEC(regs); for (i = 0; i < 3; i++) { while (sec == MSTK_REG_SEC(regs)) for (count = 0; count < 100000; count++) /* nothing */ ; prom_printf("."); sec = regs->sec; } prom_printf("\n"); /* Turn off kick start and set a "valid" time and date. */ regs->creg |= MSTK_CREG_WRITE; regs->hour &= ~MSTK_KICK_START; MSTK_SET_REG_SEC(regs,0); MSTK_SET_REG_MIN(regs,0); MSTK_SET_REG_HOUR(regs,0); MSTK_SET_REG_DOW(regs,5); MSTK_SET_REG_DOM(regs,1); MSTK_SET_REG_MONTH(regs,8); MSTK_SET_REG_YEAR(regs,1996 - MSTK_YEAR_ZERO); regs->creg &= ~MSTK_CREG_WRITE; /* Ensure the kick start bit is off. If it isn't, turn it off. */ while (regs->hour & MSTK_KICK_START) { prom_printf("CLOCK: Kick start still on!\n"); regs->creg |= MSTK_CREG_WRITE; regs->hour &= ~MSTK_KICK_START; regs->creg &= ~MSTK_CREG_WRITE; } prom_printf("CLOCK: Kick start procedure successful.\n"); } /* Return nonzero if the clock chip battery is low. */ static int has_low_battery(void) { register struct mostek48t02 *regs = mstk48t02_regs; unsigned char data1, data2; data1 = regs->eeprom[0]; /* Read some data. */ regs->eeprom[0] = ~data1; /* Write back the complement. */ data2 = regs->eeprom[0]; /* Read back the complement. */ regs->eeprom[0] = data1; /* Restore the original value. */ return (data1 == data2); /* Was the write blocked? */ } /* Probe for the real time clock chip. */ __initfunc(static void clock_probe(void)) { struct linux_prom_registers clk_reg[2]; char model[128]; register int node, cpuunit, bootbus; cpuunit = bootbus = 0; /* Determine the correct starting PROM node for the probe. */ node = prom_getchild(prom_root_node); switch (sparc_cpu_model) { case sun4c: break; case sun4m: node = prom_getchild(prom_searchsiblings(node, "obio")); break; case sun4d: node = prom_getchild(bootbus = prom_searchsiblings(prom_getchild(cpuunit = prom_searchsiblings(node, "cpu-unit")), "bootbus")); break; default: prom_printf("CLOCK: Unsupported architecture!\n"); prom_halt(); } /* Find the PROM node describing the real time clock. */ sp_clock_typ = MSTK_INVALID; node = prom_searchsiblings(node,"eeprom"); if (!node) { prom_printf("CLOCK: No clock found!\n"); prom_halt(); } /* Get the model name and setup everything up. */ model[0] = '\0'; prom_getstring(node, "model", model, sizeof(model)); if (strcmp(model, "mk48t02") == 0) { sp_clock_typ = MSTK48T02; if (prom_getproperty(node, "reg", (char *) clk_reg, sizeof(clk_reg)) == -1) { prom_printf("clock_probe: FAILED!\n"); prom_halt(); } if (sparc_cpu_model == sun4d) prom_apply_generic_ranges (bootbus, cpuunit, clk_reg, 1); else prom_apply_obio_ranges(clk_reg, 1); /* Map the clock register io area read-only */ mstk48t02_regs = (struct mostek48t02 *) sparc_alloc_io(clk_reg[0].phys_addr, (void *) 0, sizeof(*mstk48t02_regs), "clock", clk_reg[0].which_io, 0x0); mstk48t08_regs = 0; /* To catch weirdness */ } else if (strcmp(model, "mk48t08") == 0) { sp_clock_typ = MSTK48T08; if(prom_getproperty(node, "reg", (char *) clk_reg, sizeof(clk_reg)) == -1) { prom_printf("clock_probe: FAILED!\n"); prom_halt(); } if (sparc_cpu_model == sun4d) prom_apply_generic_ranges (bootbus, cpuunit, clk_reg, 1); else prom_apply_obio_ranges(clk_reg, 1); /* Map the clock register io area read-only */ mstk48t08_regs = (struct mostek48t08 *) sparc_alloc_io(clk_reg[0].phys_addr, (void *) 0, sizeof(*mstk48t08_regs), "clock", clk_reg[0].which_io, 0x0); mstk48t02_regs = &mstk48t08_regs->regs; } else { prom_printf("CLOCK: Unknown model name '%s'\n",model); prom_halt(); } /* Report a low battery voltage condition. */ if (has_low_battery()) printk(KERN_CRIT "NVRAM: Low battery voltage!\n"); /* Kick start the clock if it is completely stopped. */ if (mstk48t02_regs->sec & MSTK_STOP) kick_start_clock(); } __initfunc(void time_init(void)) { unsigned int year, mon, day, hour, min, sec; struct mostek48t02 *mregs; do_get_fast_time = do_gettimeofday; #if CONFIG_AP1000 init_timers(timer_interrupt); ap_init_time(&xtime); return; #endif clock_probe(); init_timers(timer_interrupt); mregs = mstk48t02_regs; if(!mregs) { prom_printf("Something wrong, clock regs not mapped yet.\n"); prom_halt(); } mregs->creg |= MSTK_CREG_READ; sec = MSTK_REG_SEC(mregs); min = MSTK_REG_MIN(mregs); hour = MSTK_REG_HOUR(mregs); day = MSTK_REG_DOM(mregs); mon = MSTK_REG_MONTH(mregs); year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) ); xtime.tv_sec = mktime(year, mon, day, hour, min, sec); xtime.tv_usec = 0; mregs->creg &= ~MSTK_CREG_READ; /* Now that OBP ticker has been silenced, it is safe to enable IRQ. */ __sti(); } static __inline__ unsigned long do_gettimeoffset(void) { unsigned long offset = 0; unsigned int count; count = (*master_l10_counter >> 10) & 0x1fffff; if(test_bit(TIMER_BH, &bh_active)) offset = 1000000; return offset + count; } void do_gettimeofday(struct timeval *tv) { #if CONFIG_AP1000 unsigned long flags; save_and_cli(flags); ap_gettimeofday(&xtime); *tv = xtime; restore_flags(flags); #else /* !(CONFIG_AP1000) */ /* Load doubles must be used on xtime so that what we get * is guarenteed to be atomic, this is why we can run this * with interrupts on full blast. Don't touch this... -DaveM */ __asm__ __volatile__(" sethi %hi(master_l10_counter), %o1 ld [%o1 + %lo(master_l10_counter)], %g3 sethi %hi(xtime), %g2 1: ldd [%g2 + %lo(xtime)], %o4 ld [%g3], %o1 ldd [%g2 + %lo(xtime)], %o2 xor %o4, %o2, %o2 xor %o5, %o3, %o3 orcc %o2, %o3, %g0 bne 1b cmp %o1, 0 bge 1f srl %o1, 0xa, %o1 sethi %hi(tick), %o3 ld [%o3 + %lo(tick)], %o3 sethi %hi(0x1fffff), %o2 or %o2, %lo(0x1fffff), %o2 add %o5, %o3, %o5 and %o1, %o2, %o1 1: add %o5, %o1, %o5 sethi %hi(1000000), %o2 or %o2, %lo(1000000), %o2 cmp %o5, %o2 bl,a 1f st %o4, [%o0 + 0x0] add %o4, 0x1, %o4 sub %o5, %o2, %o5 st %o4, [%o0 + 0x0] 1: st %o5, [%o0 + 0x4]"); #endif } void do_settimeofday(struct timeval *tv) { cli(); #if !CONFIG_AP1000 tv->tv_usec -= do_gettimeoffset(); if(tv->tv_usec < 0) { tv->tv_usec += 1000000; tv->tv_sec--; } #endif xtime = *tv; time_state = TIME_BAD; time_maxerror = 0x70000000; time_esterror = 0x70000000; sti(); } static int set_rtc_mmss(unsigned long nowtime) { int real_seconds, real_minutes, mostek_minutes; struct mostek48t02 *regs = mstk48t02_regs; /* Not having a register set can lead to trouble. */ if (!regs) return -1; /* Read the current RTC minutes. */ regs->creg |= MSTK_CREG_READ; mostek_minutes = MSTK_REG_MIN(regs); regs->creg &= ~MSTK_CREG_READ; /* * since we're only adjusting minutes and seconds, * don't interfere with hour overflow. This avoids * messing with unknown time zones but requires your * RTC not to be off by more than 15 minutes */ real_seconds = nowtime % 60; real_minutes = nowtime / 60; if (((abs(real_minutes - mostek_minutes) + 15)/30) & 1) real_minutes += 30; /* correct for half hour time zone */ real_minutes %= 60; if (abs(real_minutes - mostek_minutes) < 30) { regs->creg |= MSTK_CREG_WRITE; MSTK_SET_REG_SEC(regs,real_seconds); MSTK_SET_REG_MIN(regs,real_minutes); regs->creg &= ~MSTK_CREG_WRITE; } else return -1; return 0; }