patch-1.3.94 linux/arch/m68k/kernel/time.c

• Lines: 144
• Date: Sun Mar 17 18:12:32 1996
• Orig file: v1.3.93/linux/arch/m68k/kernel/time.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.93/linux/arch/m68k/kernel/time.c linux/arch/m68k/kernel/time.c
@@ -0,0 +1,143 @@
+/*
+ *  linux/arch/m68k/kernel/time.c
+ *
+ *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
+ *
+ * This file contains the m68k-specific time handling details.
+ * Most of the stuff is located in the machine specific files.
+ */
+
+#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/machdep.h>
+#include <asm/segment.h>
+#include <asm/io.h>
+
+#include <linux/timex.h>
+
+
+static inline int set_rtc_mmss(unsigned long nowtime)
+{
+  if (mach_set_clock_mmss)
+    return mach_set_clock_mmss (nowtime);
+  return -1;
+}
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+static void timer_interrupt(int irq, struct pt_regs * regs, void *dummy)
+{
+	/* last time the cmos clock got updated */
+	static long last_rtc_update=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 */
+}
+
+/* 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 */
+}
+
+void time_init(void)
+{
+	unsigned int year, mon, day, hour, min, sec;
+
+	extern void arch_gettod(int *year, int *mon, int *day, int *hour,
+				int *min, int *sec);
+
+	arch_gettod (&year, &mon, &day, &hour, &min, &sec);
+
+	if ((year += 1900) < 1970)
+		year += 100;
+	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+	xtime.tv_usec = 0;
+
+	mach_sched_init(timer_interrupt);
+}
+
+/*
+ * 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 += mach_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 -= mach_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;
+	sti();
+}