patch-2.1.34 linux/arch/sparc64/kernel/time.c

• Lines: 353
• Date: Fri Apr 11 10:47:36 1997
• Orig file: v2.1.33/linux/arch/sparc64/kernel/time.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.1.33/linux/arch/sparc64/kernel/time.c linux/arch/sparc64/kernel/time.c
@@ -0,0 +1,352 @@
+/* $Id: time.c,v 1.2 1997/04/10 03:02:35 davem Exp $
+ * time.c: UltraSparc timer and TOD clock support.
+ *
+ * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
+ *
+ * Based largely on code which is:
+ *
+ * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
+ */
+
+#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/timex.h>
+#include <linux/init.h>
+
+#include <asm/oplib.h>
+#include <asm/mostek.h>
+#include <asm/irq.h>
+#include <asm/io.h>
+
+struct mostek48t02 *mstk48t02_regs = 0;
+struct mostek48t08 *mstk48t08_regs = 0;
+struct mostek48t59 *mstk48t59_regs = 0;
+
+static int set_rtc_mmss(unsigned long);
+
+/* timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ *
+ * NOTE: On SUN5 systems the ticker interrupt comes in using 2
+ *       interrupts, one at level14 and one with softint bit 0.
+ */
+void timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
+{
+	/* last time the cmos clock got updated */
+	static long last_rtc_update=0;
+
+	do_timer(regs);
+
+	/* Determine when to update the Mostek clock. */
+	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 */
+}
+
+/* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
+static void kick_start_clock(void)
+{
+	register struct mostek48t02 *regs = mstk48t02_regs;
+	unsigned char sec;
+	int i, count;
+
+	prom_printf("CLOCK: Clock was stopped. Kick start ");
+
+	/* Turn on the kick start bit to start the oscillator. */
+	regs->creg |= MSTK_CREG_WRITE;
+	regs->sec &= ~MSTK_STOP;
+	regs->hour |= MSTK_KICK_START;
+	regs->creg &= ~MSTK_CREG_WRITE;
+
+	/* Delay to allow the clock oscillator to start. */
+	sec = MSTK_REG_SEC(regs);
+	for (i = 0; i < 3; i++) {
+		while (sec == MSTK_REG_SEC(regs))
+			for (count = 0; count < 100000; count++)
+				/* nothing */ ;
+		prom_printf(".");
+		sec = regs->sec;
+	}
+	prom_printf("\n");
+
+	/* Turn off kick start and set a "valid" time and date. */
+	regs->creg |= MSTK_CREG_WRITE;
+	regs->hour &= ~MSTK_KICK_START;
+	MSTK_SET_REG_SEC(regs,0);
+	MSTK_SET_REG_MIN(regs,0);
+	MSTK_SET_REG_HOUR(regs,0);
+	MSTK_SET_REG_DOW(regs,5);
+	MSTK_SET_REG_DOM(regs,1);
+	MSTK_SET_REG_MONTH(regs,8);
+	MSTK_SET_REG_YEAR(regs,1996 - MSTK_YEAR_ZERO);
+	regs->creg &= ~MSTK_CREG_WRITE;
+
+	/* Ensure the kick start bit is off. If it isn't, turn it off. */
+	while (regs->hour & MSTK_KICK_START) {
+		prom_printf("CLOCK: Kick start still on!\n");
+		regs->creg |= MSTK_CREG_WRITE;
+		regs->hour &= ~MSTK_KICK_START;
+		regs->creg &= ~MSTK_CREG_WRITE;
+	}
+
+	prom_printf("CLOCK: Kick start procedure successful.\n");
+}
+
+/* Return nonzero if the clock chip battery is low. */
+static int has_low_battery(void)
+{
+	register struct mostek48t02 *regs = mstk48t02_regs;
+	unsigned char data1, data2;
+
+	data1 = regs->eeprom[0];	/* Read some data. */
+	regs->eeprom[0] = ~data1;	/* Write back the complement. */
+	data2 = regs->eeprom[0];	/* Read back the complement. */
+	regs->eeprom[0] = data1;	/* Restore the original value. */
+
+	return (data1 == data2);	/* Was the write blocked? */
+}
+
+/* XXX HACK HACK HACK, delete me soon */
+static struct linux_prom_ranges XXX_sbus_ranges[PROMREG_MAX];
+static int XXX_sbus_nranges;
+
+/* Probe for the real time clock chip. */
+__initfunc(static void clock_probe(void))
+{
+	struct linux_prom_registers clk_reg[2];
+	char model[128];
+	int node, sbusnd, err;
+
+	node = prom_getchild(prom_root_node);
+	sbusnd = prom_searchsiblings(node, "sbus");
+	node = prom_getchild(sbusnd);
+
+	if(node == 0 || node == -1) {
+		prom_printf("clock_probe: Serious problem can't find sbus PROM node.\n");
+		prom_halt();
+	}
+
+	/* XXX FIX ME */
+	err = prom_getproperty(sbusnd, "ranges", (char *) XXX_sbus_ranges,
+			       sizeof(XXX_sbus_ranges));
+	if(err == -1) {
+		prom_printf("clock_probe: Cannot get XXX sbus ranges\n");
+		prom_halt();
+	}
+	XXX_sbus_nranges = (err / sizeof(struct linux_prom_ranges));
+
+	while(1) {
+		prom_getstring(node, "model", model, sizeof(model));
+		if(strcmp(model, "mk48t02") &&
+		   strcmp(model, "mk48t08") &&
+		   strcmp(model, "mk48t59")) {
+			node = prom_getsibling(node);
+			if(node == 0) {
+				prom_printf("clock_probe: Cannot find timer chip\n");
+				prom_halt();
+			}
+			continue;
+		}
+
+		err = prom_getproperty(node, "reg", (char *)clk_reg,
+				       sizeof(clk_reg));
+		if(err == -1) {
+			prom_printf("clock_probe: Cannot make Mostek\n");
+			prom_halt();
+		}
+
+		/* XXX fix me badly */
+		prom_adjust_regs(clk_reg, 1, XXX_sbus_ranges, XXX_sbus_nranges);
+
+		if(model[5] == '0' && model[6] == '2') {
+			mstk48t02_regs = (struct mostek48t02 *)
+				sparc_alloc_io(clk_reg[0].phys_addr,
+					       (void *) 0, sizeof(*mstk48t02_regs),
+					       "clock", clk_reg[0].which_io, 0x0);
+		} else if(model[5] == '0' && model[6] == '8') {
+			mstk48t08_regs = (struct mostek48t08 *)
+				sparc_alloc_io(clk_reg[0].phys_addr,
+					       (void *) 0, sizeof(*mstk48t08_regs),
+					       "clock", clk_reg[0].which_io, 0x0);
+			mstk48t02_regs = &mstk48t08_regs->regs;
+		} else {
+			mstk48t59_regs = (struct mostek48t59 *)
+				sparc_alloc_io(clk_reg[0].phys_addr,
+					       (void *) 0, sizeof(*mstk48t59_regs),
+					       "clock", clk_reg[0].which_io, 0x0);
+			mstk48t02_regs = &mstk48t59_regs->regs;
+		}
+		break;
+	}
+
+	/* Report a low battery voltage condition. */
+	if (has_low_battery())
+		prom_printf("NVRAM: Low battery voltage!\n");
+
+	/* Kick start the clock if it is completely stopped. */
+	if (mstk48t02_regs->sec & MSTK_STOP)
+		kick_start_clock();
+}
+
+#ifndef BCD_TO_BIN
+#define BCD_TO_BIN(val) (((val)&15) + ((val)>>4)*10)
+#endif
+
+#ifndef BIN_TO_BCD
+#define BIN_TO_BCD(val) ((((val)/10)<<4) + (val)%10)
+#endif
+
+__initfunc(void time_init(void))
+{
+	extern void init_timers(void (*func)(int, void *, struct pt_regs *));
+	unsigned int year, mon, day, hour, min, sec;
+	struct mostek48t02 *mregs;
+
+	do_get_fast_time = do_gettimeofday;
+
+	clock_probe();
+	init_timers(timer_interrupt);
+
+	mregs = mstk48t02_regs;
+	if(!mregs) {
+		prom_printf("Something wrong, clock regs not mapped yet.\n");
+		prom_halt();
+	}		
+
+	mregs->creg |= MSTK_CREG_READ;
+	sec = MSTK_REG_SEC(mregs);
+	min = MSTK_REG_MIN(mregs);
+	hour = MSTK_REG_HOUR(mregs);
+	day = MSTK_REG_DOM(mregs);
+	mon = MSTK_REG_MONTH(mregs);
+	year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
+	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+	xtime.tv_usec = 0;
+	mregs->creg &= ~MSTK_CREG_READ;
+}
+
+static __inline__ unsigned long do_gettimeoffset(void)
+{
+	unsigned long offset = 0;
+	unsigned int count;
+
+	/* XXX -DaveM */
+#if 0
+	count = (*master_l10_counter >> 10) & 0x1fffff;
+#else
+	count = 0;
+#endif
+
+	if(test_bit(TIMER_BH, &bh_active))
+		offset = 1000000;
+
+	return offset + count;
+}
+
+void do_gettimeofday(struct timeval *tv)
+{
+	unsigned long flags;
+
+	save_and_cli(flags);
+	*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();
+
+	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;
+	sti();
+}
+
+static int set_rtc_mmss(unsigned long nowtime)
+{
+	int real_seconds, real_minutes, mostek_minutes;
+	struct mostek48t02 *regs = mstk48t02_regs;
+
+	/* Not having a register set can lead to trouble. */
+	if (!regs) 
+		return -1;
+
+	/* Read the current RTC minutes. */
+	regs->creg |= MSTK_CREG_READ;
+	mostek_minutes = MSTK_REG_MIN(regs);
+	regs->creg &= ~MSTK_CREG_READ;
+
+	/*
+	 * 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 - mostek_minutes) + 15)/30) & 1)
+		real_minutes += 30;	/* correct for half hour time zone */
+	real_minutes %= 60;
+
+	if (abs(real_minutes - mostek_minutes) < 30) {
+		regs->creg |= MSTK_CREG_WRITE;
+		MSTK_SET_REG_SEC(regs,real_seconds);
+		MSTK_SET_REG_MIN(regs,real_minutes);
+		regs->creg &= ~MSTK_CREG_WRITE;
+	} else
+		return -1;
+
+	return 0;
+}