patch-2.1.80 linux/arch/arm/kernel/time.c

• Lines: 155
• Date: Tue Jan 20 16:39:41 1998
• Orig file: v2.1.79/linux/arch/arm/kernel/time.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.79/linux/arch/arm/kernel/time.c linux/arch/arm/kernel/time.c
@@ -0,0 +1,154 @@
+/*
+ *  linux/arch/arm/kernel/time.c
+ *
+ *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
+ *  Modifications for ARM (C) 1994, 1995, 1996,1997 Russell King
+ *
+ * This file contains the ARM-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
+ * 1997-09-10  Updated NTP code according to technical memorandum Jan '96
+ *             "A Kernel Model for Precision Timekeeping" by Dave Mills
+ */
+#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 <linux/interrupt.h>
+#include <linux/time.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/smp.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/irq.h>
+#include <asm/delay.h>
+
+#include <linux/timex.h>
+#include <asm/irq-no.h>
+#include <asm/hardware.h>
+
+extern int setup_arm_irq(int, struct irqaction *);
+extern volatile unsigned long lost_ticks;
+
+/* change this if you have some constant time drift */
+#define USECS_PER_JIFFY	(1000000/HZ)
+
+#ifndef BCD_TO_BIN
+#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
+#endif
+
+#ifndef BIN_TO_BCD
+#define BIN_TO_BCD(val) ((val)=(((val)/10)<<4) + (val)%10)
+#endif
+
+/* 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 */
+}
+
+#include <asm/arch/time.h>
+
+static unsigned long do_gettimeoffset(void)
+{
+	return gettimeoffset ();
+}
+
+void do_gettimeofday(struct timeval *tv)
+{
+	unsigned long flags;
+
+	save_flags_cli (flags);
+	*tv = xtime;
+	tv->tv_usec += do_gettimeoffset();
+
+	/*
+	 * xtime is atomically updated in timer_bh. lost_ticks is
+	 * nonzero if the tiemr 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++;
+	}
+}
+
+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 ();
+}
+
+/*
+ * 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, void *dev_id, struct pt_regs *regs)
+{
+	if (reset_timer ())
+		do_timer(regs);
+
+	update_rtc ();
+}
+
+static struct irqaction irqtimer0 = { timer_interrupt, 0, 0, "timer", NULL, NULL};
+
+void time_init(void)
+{
+	xtime.tv_sec = setup_timer();
+	xtime.tv_usec = 0;
+
+	setup_arm_irq(IRQ_TIMER0, &irqtimer0);
+}