patch-2.4.19 linux-2.4.19/arch/mips64/mips-boards/generic/time.c

• Lines: 400
• Date: Wed Dec 31 16:00:00 1969
• Orig file: linux-2.4.18/arch/mips64/mips-boards/generic/time.c
• Orig date: Sun Sep 9 10:43:02 2001

diff -urN linux-2.4.18/arch/mips64/mips-boards/generic/time.c linux-2.4.19/arch/mips64/mips-boards/generic/time.c
@@ -1,399 +0,0 @@
-/*
- * Carsten Langgaard, carstenl@mips.com
- * Copyright (C) 2000 MIPS Technologies, Inc.  All rights reserved.
- *
- * ########################################################################
- *
- *  This program is free software; you can distribute it and/or modify it
- *  under the terms of the GNU General Public License (Version 2) as
- *  published by the Free Software Foundation.
- *
- *  This program is distributed in the hope it will be useful, but WITHOUT
- *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
- *  for more details.
- *
- *  You should have received a copy of the GNU General Public License along
- *  with this program; if not, write to the Free Software Foundation, Inc.,
- *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
- *
- * ########################################################################
- *
- * Setting up the clock on the MIPS boards.
- *
- */
-
-#include <linux/config.h>
-#include <linux/init.h>
-#include <linux/kernel_stat.h>
-#include <linux/sched.h>
-#include <linux/spinlock.h>
-
-#include <asm/mipsregs.h>
-#include <asm/ptrace.h>
-
-#include <linux/mc146818rtc.h>
-#include <linux/timex.h>
-
-#include <asm/mips-boards/generic.h>
-#include <asm/mips-boards/prom.h>
-
-extern volatile unsigned long wall_jiffies;
-static long last_rtc_update = 0;
-unsigned long missed_heart_beats = 0;
-
-static unsigned long r4k_offset; /* Amount to increment compare reg each time */
-static unsigned long r4k_cur;    /* What counter should be at next timer irq */
-extern rwlock_t xtime_lock;
-
-#define ALLINTS (IE_IRQ0 | IE_IRQ1 | IE_IRQ2 | IE_IRQ3 | IE_IRQ4 | IE_IRQ5)
-
-#if defined(CONFIG_MIPS_ATLAS)
-static char display_string[] = "        LINUX ON ATLAS       ";
-#endif
-#if defined(CONFIG_MIPS_MALTA)
-static char display_string[] = "        LINUX ON MALTA       ";
-#endif
-static unsigned int display_count = 0;
-#define MAX_DISPLAY_COUNT (sizeof(display_string) - 8) 
-
-static unsigned int timer_tick_count=0;
-
-
-static inline void ack_r4ktimer(unsigned long newval)
-{
-	write_32bit_cp0_register(CP0_COMPARE, newval);
-}
-
-
-/*
- * In order to set the CMOS clock precisely, set_rtc_mmss has to be
- * called 500 ms after the second nowtime has started, because when
- * nowtime is written into the registers of the CMOS clock, it will
- * jump to the next second precisely 500 ms later. Check the Motorola
- * MC146818A or Dallas DS12887 data sheet for details.
- *
- * BUG: This routine does not handle hour overflow properly; it just
- *      sets the minutes. Usually you won't notice until after reboot!
- */
-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);
-
-	/*
-	 * 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) {
-		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;
-	}
-
-	/* 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;
-}
-
-/*
- * There are a lot of conceptually broken versions of the MIPS timer interrupt
- * handler floating around.  This one is rather different, but the algorithm
- * is provably more robust.
- */
-void mips_timer_interrupt(struct pt_regs *regs)
-{
-	int irq = 7;
-
-	if (r4k_offset == 0)
-		goto null;
-
-	do {
-		kstat.irqs[0][irq]++;
-		do_timer(regs);
-
-		/* Historical comment/code:
- 		 * RTC time of day s updated approx. every 11 
- 		 * minutes.  Because of how the numbers work out 
- 		 * we need to make absolutely sure we do this update
- 		 * within 500ms before the * next second starts, 
- 		 * thus the following code.
- 		 */
-		read_lock(&xtime_lock);
-		if ((time_status & STA_UNSYNC) == 0 
-		    && 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
-				/* do it again in 60 s */
-	    			last_rtc_update = xtime.tv_sec - 600; 
-		read_unlock(&xtime_lock);
-
-		if ((timer_tick_count++ % HZ) == 0) {
-		    mips_display_message(&display_string[display_count++]);
-		    if (display_count == MAX_DISPLAY_COUNT)
-		        display_count = 0;
-		}
-
-		r4k_cur += r4k_offset;
-		ack_r4ktimer(r4k_cur);
-
-	} while (((unsigned int)read_32bit_cp0_register(CP0_COUNT)
-	         - (unsigned int)r4k_cur) < 0x7fffffff);
-
-	return;
-
-null:
-	ack_r4ktimer(0);
-}
-
-/* 
- * Figure out the r4k offset, the amount to increment the compare
- * register for each time tick. 
- * Use the RTC to calculate offset.
- */
-static unsigned long __init cal_r4koff(void)
-{
-	unsigned long count;
-	unsigned int flags;
-
-	__save_and_cli(flags);
-
-	/* Start counter exactly on falling edge of update flag */
-	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
-	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
-
-	/* Start r4k counter. */
-	write_32bit_cp0_register(CP0_COUNT, 0);
-
-	/* Read counter exactly on falling edge of update flag */
-	while (CMOS_READ(RTC_REG_A) & RTC_UIP);
-	while (!(CMOS_READ(RTC_REG_A) & RTC_UIP));
-
-	count = read_32bit_cp0_register(CP0_COUNT);
-
-	/* restore interrupts */
-	__restore_flags(flags);
-
-	return (count / HZ);
-}
-
-static unsigned long __init get_mips_time(void)
-{
-	unsigned int year, mon, day, hour, min, sec;
-	unsigned char save_control;
-
-	save_control = CMOS_READ(RTC_CONTROL);
-
-	/* Freeze it. */
-	CMOS_WRITE(save_control | RTC_SET, RTC_CONTROL);
-
-	/* Read regs. */
-	sec = CMOS_READ(RTC_SECONDS);
-	min = CMOS_READ(RTC_MINUTES);
-	hour = CMOS_READ(RTC_HOURS);
-
-	if (!(save_control & RTC_24H))
-	{
-		if ((hour & 0xf) == 0xc)
-		        hour &= 0x80;
-	        if (hour & 0x80)
-		        hour = (hour & 0xf) + 12;     
-	}
-	day = CMOS_READ(RTC_DAY_OF_MONTH);
-	mon = CMOS_READ(RTC_MONTH);
-	year = CMOS_READ(RTC_YEAR);
-
-	/* Unfreeze clock. */
-	CMOS_WRITE(save_control, RTC_CONTROL);
-
-	if ((year += 1900) < 1970)
-	        year += 100;
-
-	return mktime(year, mon, day, hour, min, sec);
-}
-
-void __init time_init(void)
-{
-        unsigned int est_freq, flags;
-
-        /* Set Data mode - binary. */ 
-        CMOS_WRITE(CMOS_READ(RTC_CONTROL) | RTC_DM_BINARY, RTC_CONTROL);
-
-	printk("calculating r4koff... ");
-	r4k_offset = cal_r4koff();
-	printk("%08lx(%d)\n", r4k_offset, (int) r4k_offset);
-
-	est_freq = 2*r4k_offset*HZ;	
-	est_freq += 5000;    /* round */
-	est_freq -= est_freq%10000;
-	printk("CPU frequency %d.%02d MHz\n", est_freq/1000000, 
-	       (est_freq%1000000)*100/1000000);
-	r4k_cur = (read_32bit_cp0_register(CP0_COUNT) + r4k_offset);
-
-	write_32bit_cp0_register(CP0_COMPARE, r4k_cur);
-	set_cp0_status(ST0_IM, ALLINTS);
-
-	/* Read time from the RTC chipset. */
-	write_lock_irqsave (&xtime_lock, flags);
-	xtime.tv_sec = get_mips_time();
-	xtime.tv_usec = 0;
-	write_unlock_irqrestore(&xtime_lock, flags);
-}
-
-/* This is for machines which generate the exact clock. */
-#define USECS_PER_JIFFY (1000000/HZ)
-#define USECS_PER_JIFFY_FRAC (0x100000000*1000000/HZ&0xffffffff)
-
-/* Cycle counter value at the previous timer interrupt.. */
-
-static unsigned int timerhi = 0, timerlo = 0;
-
-/*
- * FIXME: Does playing with the RP bit in c0_status interfere with this code?
- */
-static unsigned long do_fast_gettimeoffset(void)
-{
-	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 (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;
-
-	__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;
-}
-
-void do_gettimeofday(struct timeval *tv)
-{
-	unsigned int flags;
-
-	read_lock_irqsave (&xtime_lock, flags);
-	*tv = xtime;
-	tv->tv_usec += do_fast_gettimeoffset();
-
-	/*
-	 * xtime is atomically updated in timer_bh. jiffies - wall_jiffies
-	 * 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)
-{
-	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_fast_gettimeoffset();
-
-	if (tv->tv_usec < 0) {
-		tv->tv_usec += 1000000;
-		tv->tv_sec--;
-	}
-
-	xtime = *tv;
-	time_adjust = 0;		/* stop active adjtime() */
-	time_status |= STA_UNSYNC;
-	time_maxerror = NTP_PHASE_LIMIT;
-	time_esterror = NTP_PHASE_LIMIT;
-
-	write_unlock_irq (&xtime_lock);
-}