patch-2.4.0-test4 linux/arch/mips/dec/time.c

• Lines: 654
• Date: Wed Jul 12 15:14:41 2000
• Orig file: v2.4.0-test3/linux/arch/mips/dec/time.c
• Orig date: Tue Aug 31 17:29:12 1999

diff -u --recursive --new-file v2.4.0-test3/linux/arch/mips/dec/time.c linux/arch/mips/dec/time.c
@@ -25,7 +25,8 @@
 #include <linux/mc146818rtc.h>
 #include <linux/timex.h>
 
-extern volatile unsigned long lost_ticks;
+extern volatile unsigned long wall_jiffies;
+extern rwlock_t xtime_lock;
 
 /*
  * Change this if you have some constant time drift
@@ -47,69 +48,69 @@
  */
 static unsigned long do_fast_gettimeoffset(void)
 {
-    u32 count;
-    unsigned long res, tmp;
+	u32 count;
+	unsigned long res, tmp;
 
-    /* Last jiffy when do_fast_gettimeoffset() was called. */
-    static unsigned long last_jiffies = 0;
-    unsigned long quotient;
-
-    /*
-     * Cached "1/(clocks per usec)*2^32" value.
-     * It has to be recalculated once each jiffy.
-     */
-    static unsigned long cached_quotient = 0;
-
-    tmp = jiffies;
-
-    quotient = cached_quotient;
-
-    if (last_jiffies != tmp) {
-	last_jiffies = tmp;
-	__asm__(".set\tnoreorder\n\t"
-		".set\tnoat\n\t"
-		".set\tmips3\n\t"
-		"lwu\t%0,%2\n\t"
-		"dsll32\t$1,%1,0\n\t"
-		"or\t$1,$1,%0\n\t"
-		"ddivu\t$0,$1,%3\n\t"
-		"mflo\t$1\n\t"
-		"dsll32\t%0,%4,0\n\t"
-		"nop\n\t"
-		"ddivu\t$0,%0,$1\n\t"
-		"mflo\t%0\n\t"
-		".set\tmips0\n\t"
-		".set\tat\n\t"
-		".set\treorder"
-      :	"=&r"(quotient)
-      :	"r"(timerhi),
-		"m"(timerlo),
-		"r"(tmp),
-		"r"(USECS_PER_JIFFY)
-      :	"$1");
-	cached_quotient = quotient;
-    }
-    /* Get last timer tick in absolute kernel time */
-    count = read_32bit_cp0_register(CP0_COUNT);
+	/* Last jiffy when do_fast_gettimeoffset() was called. */
+	static unsigned long last_jiffies = 0;
+	unsigned long quotient;
+
+	/*
+	 * Cached "1/(clocks per usec)*2^32" value.
+	 * It has to be recalculated once each jiffy.
+	 */
+	static unsigned long cached_quotient = 0;
+
+	tmp = jiffies;
+
+	quotient = cached_quotient;
+
+	if (tmp && last_jiffies != tmp) {
+		last_jiffies = tmp;
+		__asm__(".set\tnoreorder\n\t"
+			".set\tnoat\n\t"
+			".set\tmips3\n\t"
+			"lwu\t%0,%2\n\t"
+			"dsll32\t$1,%1,0\n\t"
+			"or\t$1,$1,%0\n\t"
+			"ddivu\t$0,$1,%3\n\t"
+			"mflo\t$1\n\t"
+			"dsll32\t%0,%4,0\n\t"
+			"nop\n\t"
+			"ddivu\t$0,%0,$1\n\t"
+			"mflo\t%0\n\t"
+			".set\tmips0\n\t"
+			".set\tat\n\t"
+			".set\treorder"
+			:"=&r"(quotient)
+			:"r"(timerhi),
+			"m"(timerlo),
+			"r"(tmp),
+			"r"(USECS_PER_JIFFY)
+			:"$1");
+		cached_quotient = quotient;
+	}
+	/* Get last timer tick in absolute kernel time */
+	count = read_32bit_cp0_register(CP0_COUNT);
 
-    /* .. relative to previous jiffy (32 bits is enough) */
-    count -= timerlo;
+	/* .. relative to previous jiffy (32 bits is enough) */
+	count -= timerlo;
 //printk("count: %08lx, %08lx:%08lx\n", count, timerhi, timerlo);
 
-    __asm__("multu\t%1,%2\n\t"
-	    "mfhi\t%0"
-  :	    "=r"(res)
-  :	    "r"(count),
-	    "r"(quotient));
-
-    /*
-     * Due to possible jiffies inconsistencies, we need to check 
-     * the result so that we'll get a timer that is monotonic.
-     */
-    if (res >= USECS_PER_JIFFY)
-	res = USECS_PER_JIFFY - 1;
+	__asm__("multu\t%1,%2\n\t"
+		"mfhi\t%0"
+		:"=r"(res)
+		:"r"(count),
+		"r"(quotient));
+
+	/*
+	 * Due to possible jiffies inconsistencies, we need to check 
+	 * the result so that we'll get a timer that is monotonic.
+	 */
+	if (res >= USECS_PER_JIFFY)
+		res = USECS_PER_JIFFY - 1;
 
-    return res;
+	return res;
 }
 
 /* This function must be called with interrupts disabled 
@@ -148,11 +149,11 @@
 
 static unsigned long do_slow_gettimeoffset(void)
 {
-    /*
-     * This is a kludge until I find a way for the
-     * DECstations without bus cycle counter. HK
-     */
-    return 0;
+	/*
+	 * This is a kludge until I find a way for the
+	 * DECstations without bus cycle counter. HK
+	 */
+	return 0;
 }
 
 static unsigned long (*do_gettimeoffset) (void) = do_slow_gettimeoffset;
@@ -162,47 +163,47 @@
  */
 void do_gettimeofday(struct timeval *tv)
 {
-    unsigned long flags;
+	unsigned long flags;
 
-    save_and_cli(flags);
-    *tv = xtime;
-    tv->tv_usec += do_gettimeoffset();
-
-    /*
-     * xtime is atomically updated in timer_bh. lost_ticks is
-     * nonzero if the timer bottom half hasnt executed yet.
-     */
-    if (lost_ticks)
-	tv->tv_usec += USECS_PER_JIFFY;
-
-    restore_flags(flags);
-
-    if (tv->tv_usec >= 1000000) {
-	tv->tv_usec -= 1000000;
-	tv->tv_sec++;
-    }
+	read_lock_irqsave(&xtime_lock, flags);
+	*tv = xtime;
+	tv->tv_usec += do_gettimeoffset();
+
+	/*
+	 * xtime is atomically updated in timer_bh. lost_ticks is
+	 * nonzero if the timer bottom half hasnt executed yet.
+	 */
+	if (jiffies - wall_jiffies)
+		tv->tv_usec += USECS_PER_JIFFY;
+
+	read_unlock_irqrestore(&xtime_lock, flags);
+
+	if (tv->tv_usec >= 1000000) {
+		tv->tv_usec -= 1000000;
+		tv->tv_sec++;
+	}
 }
 
 void do_settimeofday(struct timeval *tv)
 {
-    cli();
-    /* This is revolting. We need to set the xtime.tv_usec
-     * correctly. However, the value in this location is
-     * is value at the last tick.
-     * Discover what correction gettimeofday
-     * would have done, and then undo it!
-     */
-    tv->tv_usec -= do_gettimeoffset();
-
-    if (tv->tv_usec < 0) {
-	tv->tv_usec += 1000000;
-	tv->tv_sec--;
-    }
-    xtime = *tv;
-    time_state = TIME_BAD;
-    time_maxerror = MAXPHASE;
-    time_esterror = MAXPHASE;
-    sti();
+	write_lock_irq(&xtime_lock);
+	/* This is revolting. We need to set the xtime.tv_usec
+	 * correctly. However, the value in this location is
+	 * is value at the last tick.
+	 * Discover what correction gettimeofday
+	 * would have done, and then undo it!
+	 */
+	tv->tv_usec -= do_gettimeoffset();
+
+	if (tv->tv_usec < 0) {
+		tv->tv_usec += 1000000;
+		tv->tv_sec--;
+	}
+	xtime = *tv;
+	time_state = TIME_BAD;
+	time_maxerror = MAXPHASE;
+	time_esterror = MAXPHASE;
+	write_unlock_irq(&xtime_lock);
 }
 
 /*
@@ -214,53 +215,57 @@
  */
 static int set_rtc_mmss(unsigned long nowtime)
 {
-    int retval = 0;
-    int real_seconds, real_minutes, cmos_minutes;
-    unsigned char save_control, save_freq_select;
-
-    save_control = CMOS_READ(RTC_CONTROL);	/* tell the clock it's being set */
-    CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL);
-
-    save_freq_select = CMOS_READ(RTC_FREQ_SELECT);	/* stop and reset prescaler */
-    CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT);
-
-    cmos_minutes = CMOS_READ(RTC_MINUTES);
-    if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
-	BCD_TO_BIN(cmos_minutes);
-
-    /*
-     * 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 - cmos_minutes) + 15) / 30) & 1)
-	real_minutes += 30;	/* correct for half hour time zone */
-    real_minutes %= 60;
-
-    if (abs(real_minutes - cmos_minutes) < 30) {
-	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
-	    BIN_TO_BCD(real_seconds);
-	    BIN_TO_BCD(real_minutes);
+	int retval = 0;
+	int real_seconds, real_minutes, cmos_minutes;
+	unsigned char save_control, save_freq_select;
+
+	save_control = CMOS_READ(RTC_CONTROL);	/* tell the clock it's being set */
+	CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL);
+
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);	/* stop and reset prescaler */
+	CMOS_WRITE((save_freq_select | RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+	cmos_minutes = CMOS_READ(RTC_MINUTES);
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+		BCD_TO_BIN(cmos_minutes);
+
+	/*
+	 * 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 - cmos_minutes) + 15) / 30) & 1)
+		real_minutes += 30;	/* correct for half hour time zone */
+	real_minutes %= 60;
+
+	if (abs(real_minutes - cmos_minutes) < 30) {
+		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+			BIN_TO_BCD(real_seconds);
+			BIN_TO_BCD(real_minutes);
+		}
+		CMOS_WRITE(real_seconds, RTC_SECONDS);
+		CMOS_WRITE(real_minutes, RTC_MINUTES);
+	} else {
+		printk(KERN_WARNING
+		       "set_rtc_mmss: can't update from %d to %d\n",
+		       cmos_minutes, real_minutes);
+		retval = -1;
 	}
-	CMOS_WRITE(real_seconds, RTC_SECONDS);
-	CMOS_WRITE(real_minutes, RTC_MINUTES);
-    } else
-	retval = -1;
-
-    /* The following flags have to be released exactly in this order,
-     * otherwise the DS12887 (popular MC146818A clone with integrated
-     * battery and quartz) will not reset the oscillator and will not
-     * update precisely 500 ms later. You won't find this mentioned in
-     * the Dallas Semiconductor data sheets, but who believes data
-     * sheets anyway ...                           -- Markus Kuhn
-     */
-    CMOS_WRITE(save_control, RTC_CONTROL);
-    CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
 
-    return retval;
+	/* The following flags have to be released exactly in this order,
+	 * otherwise the DS12887 (popular MC146818A clone with integrated
+	 * battery and quartz) will not reset the oscillator and will not
+	 * update precisely 500 ms later. You won't find this mentioned in
+	 * the Dallas Semiconductor data sheets, but who believes data
+	 * sheets anyway ...                           -- Markus Kuhn
+	 */
+	CMOS_WRITE(save_control, RTC_CONTROL);
+	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+
+	return retval;
 }
 
 /* last time the cmos clock got updated */
@@ -271,40 +276,74 @@
  * as well as call the "do_timer()" routine every clocktick
  */
 static void inline
- timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
+timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
-    volatile unsigned char dummy;
+	volatile unsigned char dummy;
 
-    dummy = CMOS_READ(RTC_REG_C);	/* ACK RTC Interrupt */
-    do_timer(regs);
+	dummy = CMOS_READ(RTC_REG_C);	/* ACK RTC Interrupt */
 
-    /*
-     * If we have an externally synchronized Linux clock, then update
-     * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
-     * called as close as possible to 500 ms before the new second starts.
-     */
-    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 */
+	if (!user_mode(regs)) {
+		if (prof_buffer && current->pid) {
+			extern int _stext;
+			unsigned long pc = regs->cp0_epc;
+
+			pc -= (unsigned long) &_stext;
+			pc >>= prof_shift;
+			/*
+			 * Dont ignore out-of-bounds pc values silently,
+			 * put them into the last histogram slot, so if
+			 * present, they will show up as a sharp peak.
+			 */
+			if (pc > prof_len - 1)
+				pc = prof_len - 1;
+			atomic_inc((atomic_t *) & prof_buffer[pc]);
+		}
+	}
+	do_timer(regs);
+
+	/*
+	 * If we have an externally synchronized Linux clock, then update
+	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
+	 * called as close as possible to 500 ms before the new second starts.
+	 */
+	read_lock(&xtime_lock);
+	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 */
+	/* As we return to user mode fire off the other CPU schedulers.. this is
+	   basically because we don't yet share IRQ's around. This message is
+	   rigged to be safe on the 386 - basically it's a hack, so don't look
+	   closely for now.. */
+	/*smp_message_pass(MSG_ALL_BUT_SELF, MSG_RESCHEDULE, 0L, 0); */
+	read_unlock(&xtime_lock);
 }
 
 static void r4k_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
-    unsigned int count;
-
-    /*
-     * The cycle counter is only 32 bit which is good for about
-     * a minute at current count rates of upto 150MHz or so.
-     */
-    count = read_32bit_cp0_register(CP0_COUNT);
-    timerhi += (count < timerlo);	/* Wrap around */
-    timerlo = count;
+	unsigned int count;
 
-    timer_interrupt(irq, dev_id, regs);
+	/*
+	 * The cycle counter is only 32 bit which is good for about
+	 * a minute at current count rates of upto 150MHz or so.
+	 */
+	count = read_32bit_cp0_register(CP0_COUNT);
+	timerhi += (count < timerlo);	/* Wrap around */
+	timerlo = count;
+
+	timer_interrupt(irq, dev_id, regs);
+
+	if (!jiffies) {
+		/*
+		 * If jiffies has overflowed in this timer_interrupt we must
+		 * update the timer[hi]/[lo] to make do_fast_gettimeoffset()
+		 * quotient calc still valid. -arca
+		 */
+		timerhi = timerlo = 0;
+	}
 }
 
 /* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
@@ -326,114 +365,114 @@
 				   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 */
+	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 */
 }
 
 char cyclecounter_available;
 
 static inline void init_cycle_counter(void)
 {
-    switch (mips_cputype) {
-    case CPU_UNKNOWN:
-    case CPU_R2000:
-    case CPU_R3000:
-    case CPU_R3000A:
-    case CPU_R3041:
-    case CPU_R3051:
-    case CPU_R3052:
-    case CPU_R3081:
-    case CPU_R3081E:
-    case CPU_R6000:
-    case CPU_R6000A:
-    case CPU_R8000:		/* Not shure about that one, play safe */
-	cyclecounter_available = 0;
-	break;
-    case CPU_R4000PC:
-    case CPU_R4000SC:
-    case CPU_R4000MC:
-    case CPU_R4200:
-    case CPU_R4400PC:
-    case CPU_R4400SC:
-    case CPU_R4400MC:
-    case CPU_R4600:
-    case CPU_R10000:
-    case CPU_R4300:
-    case CPU_R4650:
-    case CPU_R4700:
-    case CPU_R5000:
-    case CPU_R5000A:
-    case CPU_R4640:
-    case CPU_NEVADA:
-	cyclecounter_available = 1;
-	break;
-    }
+	switch (mips_cputype) {
+	case CPU_UNKNOWN:
+	case CPU_R2000:
+	case CPU_R3000:
+	case CPU_R3000A:
+	case CPU_R3041:
+	case CPU_R3051:
+	case CPU_R3052:
+	case CPU_R3081:
+	case CPU_R3081E:
+	case CPU_R6000:
+	case CPU_R6000A:
+	case CPU_R8000:	/* Not shure about that one, play safe */
+		cyclecounter_available = 0;
+		break;
+	case CPU_R4000PC:
+	case CPU_R4000SC:
+	case CPU_R4000MC:
+	case CPU_R4200:
+	case CPU_R4400PC:
+	case CPU_R4400SC:
+	case CPU_R4400MC:
+	case CPU_R4600:
+	case CPU_R10000:
+	case CPU_R4300:
+	case CPU_R4650:
+	case CPU_R4700:
+	case CPU_R5000:
+	case CPU_R5000A:
+	case CPU_R4640:
+	case CPU_NEVADA:
+		cyclecounter_available = 1;
+		break;
+	}
 }
 
-struct irqaction irq0 =
-{timer_interrupt, SA_INTERRUPT, 0,
- "timer", NULL, NULL};
-
+struct irqaction irq0 = {timer_interrupt, SA_INTERRUPT, 0,
+			 "timer", NULL, NULL};
 
 void (*board_time_init) (struct irqaction * irq);
 
 void __init time_init(void)
 {
-    unsigned int year, mon, day, hour, min, sec;
-    int i;
+	unsigned int year, mon, day, hour, min, sec;
+	int i;
 
-    /* The Linux interpretation of the CMOS clock register contents:
-     * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
-     * RTC registers show the second which has precisely just started.
-     * Let's hope other operating systems interpret the RTC the same way.
-     */
-    /* read RTC exactly on falling edge of update flag */
-    for (i = 0; i < 1000000; i++)	/* may take up to 1 second... */
-	if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
-	    break;
-    for (i = 0; i < 1000000; i++)	/* must try at least 2.228 ms */
-	if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
-	    break;
-    do {			/* Isn't this overkill ? UIP above should guarantee consistency */
-	sec = CMOS_READ(RTC_SECONDS);
-	min = CMOS_READ(RTC_MINUTES);
-	hour = CMOS_READ(RTC_HOURS);
-	day = CMOS_READ(RTC_DAY_OF_MONTH);
-	mon = CMOS_READ(RTC_MONTH);
-	year = CMOS_READ(RTC_YEAR);
-    } while (sec != CMOS_READ(RTC_SECONDS));
-    if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
-	BCD_TO_BIN(sec);
-	BCD_TO_BIN(min);
-	BCD_TO_BIN(hour);
-	BCD_TO_BIN(day);
-	BCD_TO_BIN(mon);
-	BCD_TO_BIN(year);
-    }
-    /*
-     * The DECstation RTC is used as a TOY (Time Of Year).
-     * The PROM will reset the year to either '70, '71 or '72.
-     * This hack will only work until Dec 31 2001.
-     */
-    year += 1927;
-
-    xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
-    xtime.tv_usec = 0;
-
-    init_cycle_counter();
-
-    if (cyclecounter_available) {
-	write_32bit_cp0_register(CP0_COUNT, 0);
-	do_gettimeoffset = do_fast_gettimeoffset;
-	irq0.handler = r4k_timer_interrupt;
-    }
-    board_time_init(&irq0);
+	/* The Linux interpretation of the CMOS clock register contents:
+	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+	 * RTC registers show the second which has precisely just started.
+	 * Let's hope other operating systems interpret the RTC the same way.
+	 */
+	/* read RTC exactly on falling edge of update flag */
+	for (i = 0; i < 1000000; i++)	/* may take up to 1 second... */
+		if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
+			break;
+	for (i = 0; i < 1000000; i++)	/* must try at least 2.228 ms */
+		if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
+			break;
+	do {			/* Isn't this overkill ? UIP above should guarantee consistency */
+		sec = CMOS_READ(RTC_SECONDS);
+		min = CMOS_READ(RTC_MINUTES);
+		hour = CMOS_READ(RTC_HOURS);
+		day = CMOS_READ(RTC_DAY_OF_MONTH);
+		mon = CMOS_READ(RTC_MONTH);
+		year = CMOS_READ(RTC_YEAR);
+	} while (sec != CMOS_READ(RTC_SECONDS));
+	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BCD_TO_BIN(sec);
+		BCD_TO_BIN(min);
+		BCD_TO_BIN(hour);
+		BCD_TO_BIN(day);
+		BCD_TO_BIN(mon);
+		BCD_TO_BIN(year);
+	}
+	/*
+	 * The DECstation RTC is used as a TOY (Time Of Year).
+	 * The PROM will reset the year to either '70, '71 or '72.
+	 * This hack will only work until Dec 31 2001.
+	 */
+	year += 1928;
+
+	write_lock_irq(&xtime_lock);
+	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+	xtime.tv_usec = 0;
+	write_unlock_irq(&xtime_lock);
+
+	init_cycle_counter();
+
+	if (cyclecounter_available) {
+		write_32bit_cp0_register(CP0_COUNT, 0);
+		do_gettimeoffset = do_fast_gettimeoffset;
+		irq0.handler = r4k_timer_interrupt;
+	}
+	board_time_init(&irq0);
 }