patch-2.1.48 linux/arch/ppc/kernel/time.c

• Lines: 466
• Date: Wed Dec 31 16:00:00 1969
• Orig file: v2.1.47/linux/arch/ppc/kernel/time.c
• Orig date: Wed Dec 18 00:49:52 1996

diff -u --recursive --new-file v2.1.47/linux/arch/ppc/kernel/time.c linux/arch/ppc/kernel/time.c
@@ -1,465 +0,0 @@
-/*
- *  linux/arch/i386/kernel/time.c
- *
- *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
- *
- * Adapted for PowerPC (PreP) by Gary Thomas
- *
- * This file contains the PC-specific time handling details:
- * reading the RTC at bootup, etc..
- * 1994-07-02    Alan Modra
- *	fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
- * 1995-03-26    Markus Kuhn
- *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
- *      precision CMOS clock update
- */
-#include <linux/errno.h>
-#include <linux/sched.h>
-#include <linux/kernel.h>
-#include <linux/param.h>
-#include <linux/string.h>
-#include <linux/mm.h>
-
-#include <asm/segment.h>
-#include <asm/io.h>
-#include <asm/nvram.h>
-#include <asm/mc146818rtc.h>
-#include <asm/processor.h>
-
-#include <linux/timex.h>
-#include <linux/config.h>
-
-extern int isBeBox[];
-
-#define TIMER_IRQ 0
-
-/* Cycle counter value at the previous timer interrupt.. */
-static unsigned long long last_timer_cc = 0;
-static unsigned long long init_timer_cc = 0;
-
-static inline int CMOS_READ(int addr)
-{
-	outb(addr>>8, NVRAM_AS1);
-	outb(addr, NVRAM_AS0);
-	return (inb(NVRAM_DATA));
-}
-
-static inline int CMOS_WRITE(int addr, int val)
-{
-	outb(addr>>8, NVRAM_AS1);
-	outb(addr, NVRAM_AS0);
-	return (outb(val, NVRAM_DATA));
-}
-
-/* This function must be called with interrupts disabled 
- * It was inspired by Steve McCanne's microtime-i386 for BSD.  -- jrs
- * 
- * However, the pc-audio speaker driver changes the divisor so that
- * it gets interrupted rather more often - it loads 64 into the
- * counter rather than 11932! This has an adverse impact on
- * do_gettimeoffset() -- it stops working! What is also not
- * good is that the interval that our timer function gets called
- * is no longer 10.0002 ms, but 9.9767 ms. To get around this
- * would require using a different timing source. Maybe someone
- * could use the RTC - I know that this can interrupt at frequencies
- * ranging from 8192Hz to 2Hz. If I had the energy, I'd somehow fix
- * it so that at startup, the timer code in sched.c would select
- * using either the RTC or the 8253 timer. The decision would be
- * based on whether there was any other device around that needed
- * to trample on the 8253. I'd set up the RTC to interrupt at 1024 Hz,
- * and then do some jiggery to have a version of do_timer that 
- * advanced the clock by 1/1024 s. Every time that reached over 1/100
- * of a second, then do all the old code. If the time was kept correct
- * then do_gettimeoffset could just return 0 - there is no low order
- * divider that can be accessed.
- *
- * Ideally, you would be able to use the RTC for the speaker driver,
- * but it appears that the speaker driver really needs interrupt more
- * often than every 120 us or so.
- *
- * Anyway, this needs more thought....		pjsg (1993-08-28)
- * 
- * If you are really that interested, you should be reading
- * comp.protocols.time.ntp!
- */
-
-#define TICK_SIZE tick
-
-static unsigned long do_slow_gettimeoffset(void)
-{
-	int count;
-	unsigned long offset = 0;
-
-	/* timer count may underflow right here */
-	outb_p(0x00, 0x43);	/* latch the count ASAP */
-	count = inb_p(0x40);	/* read the latched count */
-	count |= inb(0x40) << 8;
-	/* we know probability of underflow is always MUCH less than 1% */
-	if (count > (LATCH - LATCH/100)) {
-		/* check for pending timer interrupt */
-		outb_p(0x0a, 0x20);
-		if (inb(0x20) & 1)
-			offset = TICK_SIZE;
-	}
-	count = ((LATCH-1) - count) * TICK_SIZE;
-	count = (count + LATCH/2) / LATCH;
-	return offset + count;
-}
-
-static unsigned long (*do_gettimeoffset)(void) = do_slow_gettimeoffset;
-
-/*
- * This version of gettimeofday has near microsecond resolution.
- */
-void do_gettimeofday(struct timeval *tv)
-{
-	unsigned long flags;
-
-	save_flags(flags);
-	cli();
-	*tv = xtime;
-	tv->tv_usec += do_gettimeoffset();
-	if (tv->tv_usec >= 1000000) {
-		tv->tv_usec -= 1000000;
-		tv->tv_sec++;
-	}
-	restore_flags(flags);
-}
-
-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 = 0x70000000;
-	time_esterror = 0x70000000;
-	set_rtc(xtime.tv_sec);
-	sti();
-}
-
-static int      month_days[12] = {
-	31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
-};
-
-#define FEBRUARY	2
-#define	STARTOFTIME	1970
-#define SECDAY		86400L
-#define SECYR		(SECDAY * 365)
-#define	leapyear(year)		((year) % 4 == 0)
-#define	days_in_year(a) 	(leapyear(a) ? 366 : 365)
-#define	days_in_month(a) 	(month_days[(a) - 1])
-
-struct _tm
-{
-	int             tm_sec;
-	int             tm_min;
-	int             tm_hour;
-	int             tm_day;
-	int             tm_month;
-	int             tm_year;
-};
-
-static _to_tm(int tim, struct _tm * tm)
-{
-	register int    i;
-	register long   hms, day;
-
-	day = tim / SECDAY;
-	hms = tim % SECDAY;
-
-	/* Hours, minutes, seconds are easy */
-	tm->tm_hour = hms / 3600;
-	tm->tm_min = (hms % 3600) / 60;
-	tm->tm_sec = (hms % 3600) % 60;
-
-	/* Number of years in days */
-	for (i = STARTOFTIME; day >= days_in_year(i); i++)
-		day -= days_in_year(i);
-	tm->tm_year = i;
-
-	/* Number of months in days left */
-	if (leapyear(tm->tm_year))
-		days_in_month(FEBRUARY) = 29;
-	for (i = 1; day >= days_in_month(i); i++)
-		day -= days_in_month(i);
-	days_in_month(FEBRUARY) = 28;
-	tm->tm_month = i;
-
-	/* Days are what is left over (+1) from all that. */
-	tm->tm_day = day + 1;
-}
-
-/*
- * Set the time into the CMOS
- */
-static void set_rtc(unsigned long nowtime)
-{
-  int retval = 0;
-  struct _tm tm;
-  unsigned char save_control, save_freq_select;
-  
-  /*if (_Processor != _PROC_IBM) return;*/
-  
-  _to_tm(nowtime, &tm);
-  
-  /* tell the clock it's being set */  
-  save_control = CMOS_MCRTC_READ(MCRTC_CONTROL); 
-  CMOS_MCRTC_WRITE((save_control|MCRTC_SET), MCRTC_CONTROL);
-  /* stop and reset prescaler */  
-  save_freq_select = CMOS_MCRTC_READ(MCRTC_FREQ_SELECT);
-  CMOS_MCRTC_WRITE((save_freq_select|MCRTC_DIV_RESET2), MCRTC_FREQ_SELECT);
-
-  printk("Set RTC H:M:S M/D/Y %d:%02d:%02d %d/%d/%d\n", 
-       tm.tm_hour, tm.tm_min, tm.tm_sec, tm.tm_month, tm.tm_day, tm.tm_year);
-	if (!(save_control & MCRTC_DM_BINARY) || MCRTC_ALWAYS_BCD) {
-		BIN_TO_BCD(tm.tm_sec);
-		BIN_TO_BCD(tm.tm_min);
-		BIN_TO_BCD(tm.tm_hour);
-		BIN_TO_BCD(tm.tm_month);
-		BIN_TO_BCD(tm.tm_day);
-		BIN_TO_BCD(tm.tm_year);
-	}
-
-	CMOS_MCRTC_WRITE(tm.tm_sec,  MCRTC_SECONDS);
-	CMOS_MCRTC_WRITE(tm.tm_min,  MCRTC_MINUTES);
-	CMOS_MCRTC_WRITE(tm.tm_hour, MCRTC_HOURS);
-	CMOS_MCRTC_WRITE(tm.tm_month,  MCRTC_MONTH);
-	CMOS_MCRTC_WRITE(tm.tm_day,  MCRTC_MINUTES);
-	CMOS_MCRTC_WRITE(tm.tm_year - 1900, MCRTC_MINUTES);
-
-	/* 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_MCRTC_WRITE(save_control, MCRTC_CONTROL);
-	CMOS_MCRTC_WRITE(save_freq_select, MCRTC_FREQ_SELECT);
-}
-
-/*
- * 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.
- */
-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;
-
-#ifdef __powerpc__
-printk("%s: %d - set TOD\n", __FILE__, __LINE__);
-return (-1);  /* Not implemented */
-#else	
-
-printk("%s: %d - set TOD\n", __FILE__, __LINE__);
-	save_control = CMOS_MCRTC_READ(MCRTC_CONTROL); /* tell the clock it's being set */
-	CMOS_MCRTC_WRITE((save_control|MCRTC_SET), MCRTC_CONTROL);
-
-	save_freq_select = CMOS_MCRTC_READ(MCRTC_FREQ_SELECT); /* stop and reset prescaler */
-	CMOS_MCRTC_WRITE((save_freq_select|MCRTC_DIV_RESET2), MCRTC_FREQ_SELECT);
-
-	cmos_minutes = CMOS_MCRTC_READ(MCRTC_MINUTES);
-	if (!(save_control & MCRTC_DM_BINARY) || MCRTC_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 & MCRTC_DM_BINARY) || MCRTC_ALWAYS_BCD) {
-			BIN_TO_BCD(real_seconds);
-			BIN_TO_BCD(real_minutes);
-		}
-		CMOS_MCRTC_WRITE(real_seconds,MCRTC_SECONDS);
-		CMOS_MCRTC_WRITE(real_minutes,MCRTC_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_MCRTC_WRITE(save_control, MCRTC_CONTROL);
-	CMOS_MCRTC_WRITE(save_freq_select, MCRTC_FREQ_SELECT);
-
-	return retval;
-#endif	
-}
-
-/* last time the cmos clock got updated */
-static long last_rtc_update = 0;
-
-/*
- * timer_interrupt() needs to keep up the real-time clock,
- * as well as call the "do_timer()" routine every clocktick
- */
-static inline void timer_interrupt(int irq, void *dev, struct pt_regs * regs)
-{
-  static int timeints = 0;
-  
-  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.
-   */
-  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 */
-
-
-  /* use hard disk LED as a heartbeat instead -- much more useful
-     -- Cort */
-  switch(timeints)
-  {
-    /* act like an actual heart beat -- ie thump-thump-pause... */
-    case 0:
-    case 20:
-      hard_disk_LED(1);
-      break;
-    case 7:
-    case 27:
-      hard_disk_LED(0);
-      break;
-    case 100:
-      timeints = -1;
-      break;
-  }
-  timeints++;
-}
-
-/* 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 */
-}
-
-unsigned long get_cmos_time(void)
-{
-  unsigned int year, mon, day, hour, min, sec;
-  int i;
-  
-  if (_Processor == _PROC_IBM)
-  {
-    do { /* Isn't this overkill ? UIP above should guarantee consistency */
-      sec = CMOS_MCRTC_READ(MCRTC_SECONDS);
-      min = CMOS_MCRTC_READ(MCRTC_MINUTES);
-      hour = CMOS_MCRTC_READ(MCRTC_HOURS);
-      day = CMOS_MCRTC_READ(MCRTC_DAY_OF_MONTH);
-      mon = CMOS_MCRTC_READ(MCRTC_MONTH);
-      year = CMOS_MCRTC_READ(MCRTC_YEAR);
-    } while (sec != CMOS_MCRTC_READ(MCRTC_SECONDS));
-    BCD_TO_BIN(sec);
-    BCD_TO_BIN(min);
-    BCD_TO_BIN(hour);
-    BCD_TO_BIN(day);
-    BCD_TO_BIN(mon);
-    BCD_TO_BIN(year);
-  } else
-    if (_Processor == _PROC_Be)
-      {
-	do { /* Isn't this overkill ? UIP above should guarantee consistency */
-	  sec = CMOS_MCRTC_READ(MCRTC_SECONDS);
-	  min = CMOS_MCRTC_READ(MCRTC_MINUTES);
-	  hour = CMOS_MCRTC_READ(MCRTC_HOURS);
-	  day = CMOS_MCRTC_READ(MCRTC_DAY_OF_MONTH);
-	  mon = CMOS_MCRTC_READ(MCRTC_MONTH);
-	  year = CMOS_MCRTC_READ(MCRTC_YEAR);
-	} while (sec != CMOS_MCRTC_READ(MCRTC_SECONDS));
-      } else
-	{ /* Motorola PowerStack etc. */
-	  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));
-	  BCD_TO_BIN(sec);
-	  BCD_TO_BIN(min);
-	  BCD_TO_BIN(hour);
-	  BCD_TO_BIN(day);
-	  BCD_TO_BIN(mon);
-	  BCD_TO_BIN(year);
-	}
-#if 0	
-printk("CMOS TOD - M/D/Y H:M:S = %d/%d/%d %d:%02d:%02d\n", mon, day, year, hour, min, sec);
-#endif
-	if ((year += 1900) < 1970)
-		year += 100;
-	return mktime(year, mon, day, hour, min, sec);
-}
-
-void time_init(void)
-{
-  void (*irq_handler)(int, struct pt_regs *);
-  xtime.tv_sec = get_cmos_time();
-  xtime.tv_usec = 0;
-  
-  /* If we have the CPU hardware time counters, use them */
-  irq_handler = timer_interrupt;
-  if (request_irq(TIMER_IRQ, irq_handler, 0, "timer", NULL) != 0)
-    panic("Could not allocate timer IRQ!");
-}
-