time.c

来自「优龙2410linux2.6.8内核源代码」· C语言 代码 · 共 1,282 行 · 第 1/3 页

	static long last_rtc_update;

	/* Determine when to update the Mostek clock. */
	if ((time_status & STA_UNSYNC) == 0 &&
	    xtime.tv_sec > last_rtc_update + 660 &&
	    (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
	    (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 2) {
		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 */
	}
}

void sparc64_do_profile(struct pt_regs *regs)
{
	unsigned long pc;

	profile_hook(regs);

	if (user_mode(regs))
		return;

	if (!prof_buffer)
		return;

	pc = regs->tpc;

	pc -= (unsigned long) _stext;
	pc >>= prof_shift;

	if(pc >= prof_len)
		pc = prof_len - 1;
	atomic_inc((atomic_t *)&prof_buffer[pc]);
}

static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	unsigned long ticks, pstate;

	write_seqlock(&xtime_lock);

	do {
#ifndef CONFIG_SMP
		sparc64_do_profile(regs);
#endif
		do_timer(regs);

		/* Guarantee that the following sequences execute
		 * uninterrupted.
		 */
		__asm__ __volatile__("rdpr	%%pstate, %0\n\t"
				     "wrpr	%0, %1, %%pstate"
				     : "=r" (pstate)
				     : "i" (PSTATE_IE));

		timer_tick_compare = tick_ops->add_compare(timer_tick_offset);
		ticks = tick_ops->get_tick();

		/* Restore PSTATE_IE. */
		__asm__ __volatile__("wrpr	%0, 0x0, %%pstate"
				     : /* no outputs */
				     : "r" (pstate));
	} while (time_after_eq(ticks, timer_tick_compare));

	timer_check_rtc();

	write_sequnlock(&xtime_lock);

	return IRQ_HANDLED;
}

#ifdef CONFIG_SMP
void timer_tick_interrupt(struct pt_regs *regs)
{
	write_seqlock(&xtime_lock);

	do_timer(regs);

	/*
	 * Only keep timer_tick_offset uptodate, but don't set TICK_CMPR.
	 */
	timer_tick_compare = tick_ops->get_compare() + timer_tick_offset;

	timer_check_rtc();

	write_sequnlock(&xtime_lock);
}
#endif

/* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
static void __init kick_start_clock(void)
{
	unsigned long regs = mstk48t02_regs;
	u8 sec, tmp;
	int i, count;

	prom_printf("CLOCK: Clock was stopped. Kick start ");

	spin_lock_irq(&mostek_lock);

	/* Turn on the kick start bit to start the oscillator. */
	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp |= MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);
	tmp = mostek_read(regs + MOSTEK_SEC);
	tmp &= ~MSTK_STOP;
	mostek_write(regs + MOSTEK_SEC, tmp);
	tmp = mostek_read(regs + MOSTEK_HOUR);
	tmp |= MSTK_KICK_START;
	mostek_write(regs + MOSTEK_HOUR, tmp);
	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp &= ~MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);

	spin_unlock_irq(&mostek_lock);

	/* 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 = MSTK_REG_SEC(regs);
	}
	prom_printf("\n");

	spin_lock_irq(&mostek_lock);

	/* Turn off kick start and set a "valid" time and date. */
	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp |= MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);
	tmp = mostek_read(regs + MOSTEK_HOUR);
	tmp &= ~MSTK_KICK_START;
	mostek_write(regs + MOSTEK_HOUR, tmp);
	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);
	tmp = mostek_read(regs + MOSTEK_CREG);
	tmp &= ~MSTK_CREG_WRITE;
	mostek_write(regs + MOSTEK_CREG, tmp);

	spin_unlock_irq(&mostek_lock);

	/* Ensure the kick start bit is off. If it isn't, turn it off. */
	while (mostek_read(regs + MOSTEK_HOUR) & MSTK_KICK_START) {
		prom_printf("CLOCK: Kick start still on!\n");

		spin_lock_irq(&mostek_lock);

		tmp = mostek_read(regs + MOSTEK_CREG);
		tmp |= MSTK_CREG_WRITE;
		mostek_write(regs + MOSTEK_CREG, tmp);

		tmp = mostek_read(regs + MOSTEK_HOUR);
		tmp &= ~MSTK_KICK_START;
		mostek_write(regs + MOSTEK_HOUR, tmp);

		tmp = mostek_read(regs + MOSTEK_CREG);
		tmp &= ~MSTK_CREG_WRITE;
		mostek_write(regs + MOSTEK_CREG, tmp);

		spin_unlock_irq(&mostek_lock);
	}

	prom_printf("CLOCK: Kick start procedure successful.\n");
}

/* Return nonzero if the clock chip battery is low. */
static int __init has_low_battery(void)
{
	unsigned long regs = mstk48t02_regs;
	u8 data1, data2;

	spin_lock_irq(&mostek_lock);

	data1 = mostek_read(regs + MOSTEK_EEPROM);	/* Read some data. */
	mostek_write(regs + MOSTEK_EEPROM, ~data1);	/* Write back the complement. */
	data2 = mostek_read(regs + MOSTEK_EEPROM);	/* Read back the complement. */
	mostek_write(regs + MOSTEK_EEPROM, data1);	/* Restore original value. */

	spin_unlock_irq(&mostek_lock);

	return (data1 == data2);	/* Was the write blocked? */
}

/* Probe for the real time clock chip. */
static void __init set_system_time(void)
{
	unsigned int year, mon, day, hour, min, sec;
	unsigned long mregs = mstk48t02_regs;
#ifdef CONFIG_PCI
	unsigned long dregs = ds1287_regs;
#else
	unsigned long dregs = 0UL;
#endif
	u8 tmp;

	if (!mregs && !dregs) {
		prom_printf("Something wrong, clock regs not mapped yet.\n");
		prom_halt();
	}		

	if (mregs) {
		spin_lock_irq(&mostek_lock);

		/* Traditional Mostek chip. */
		tmp = mostek_read(mregs + MOSTEK_CREG);
		tmp |= MSTK_CREG_READ;
		mostek_write(mregs + MOSTEK_CREG, tmp);

		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) );
	} else {
		int i;

		/* Dallas 12887 RTC chip. */

		/* Stolen from arch/i386/kernel/time.c, see there for
		 * credits and descriptive comments.
		 */
		for (i = 0; i < 1000000; i++) {
			if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)
				break;
			udelay(10);
		}
		for (i = 0; i < 1000000; i++) {
			if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
				break;
			udelay(10);
		}
		do {
			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));
		if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
			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 ((year += 1900) < 1970)
			year += 100;
	}

	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
	xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
	set_normalized_timespec(&wall_to_monotonic,
 	                        -xtime.tv_sec, -xtime.tv_nsec);

	if (mregs) {
		tmp = mostek_read(mregs + MOSTEK_CREG);
		tmp &= ~MSTK_CREG_READ;
		mostek_write(mregs + MOSTEK_CREG, tmp);

		spin_unlock_irq(&mostek_lock);
	}
}

void __init clock_probe(void)
{
	struct linux_prom_registers clk_reg[2];
	char model[128];
	int node, busnd = -1, err;
	unsigned long flags;
	struct linux_central *cbus;
#ifdef CONFIG_PCI
	struct linux_ebus *ebus = NULL;
	struct sparc_isa_bridge *isa_br = NULL;
#endif
	static int invoked;

	if (invoked)
		return;
	invoked = 1;


	if (this_is_starfire) {
		/* davem suggests we keep this within the 4M locked kernel image */
		static char obp_gettod[256];
		static u32 unix_tod;

		sprintf(obp_gettod, "h# %08x unix-gettod",
			(unsigned int) (long) &unix_tod);
		prom_feval(obp_gettod);
		xtime.tv_sec = unix_tod;
		xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
		set_normalized_timespec(&wall_to_monotonic,
		                        -xtime.tv_sec, -xtime.tv_nsec);
		return;
	}

	local_irq_save(flags);

	cbus = central_bus;
	if (cbus != NULL)
		busnd = central_bus->child->prom_node;

	/* Check FHC Central then EBUSs then ISA bridges then SBUSs.
	 * That way we handle the presence of multiple properly.
	 *
	 * As a special case, machines with Central must provide the
	 * timer chip there.
	 */
#ifdef CONFIG_PCI
	if (ebus_chain != NULL) {
		ebus = ebus_chain;
		if (busnd == -1)
			busnd = ebus->prom_node;
	}
	if (isa_chain != NULL) {
		isa_br = isa_chain;
		if (busnd == -1)
			busnd = isa_br->prom_node;
	}
#endif
	if (sbus_root != NULL && busnd == -1)
		busnd = sbus_root->prom_node;

	if (busnd == -1) {
		prom_printf("clock_probe: problem, cannot find bus to search.\n");
		prom_halt();
	}

	node = prom_getchild(busnd);

	while (1) {
		if (!node)
			model[0] = 0;
		else
			prom_getstring(node, "model", model, sizeof(model));
		if (strcmp(model, "mk48t02") &&
		    strcmp(model, "mk48t08") &&
		    strcmp(model, "mk48t59") &&
		    strcmp(model, "m5819") &&
		    strcmp(model, "m5819p") &&
		    strcmp(model, "ds1287")) {
			if (cbus != NULL) {
				prom_printf("clock_probe: Central bus lacks timer chip.\n");
				prom_halt();
			}

		   	if (node != 0)
				node = prom_getsibling(node);
#ifdef CONFIG_PCI
			while ((node == 0) && ebus != NULL) {
				ebus = ebus->next;
				if (ebus != NULL) {
					busnd = ebus->prom_node;
					node = prom_getchild(busnd);
				}
			}
			while ((node == 0) && isa_br != NULL) {
				isa_br = isa_br->next;
				if (isa_br != NULL) {
					busnd = isa_br->prom_node;
					node = prom_getchild(busnd);
				}
			}
#endif
			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 get Mostek reg property\n");
			prom_halt();
		}

		if (cbus != NULL) {
			apply_fhc_ranges(central_bus->child, clk_reg, 1);
			apply_central_ranges(central_bus, clk_reg, 1);
		}
#ifdef CONFIG_PCI
		else if (ebus != NULL) {
			struct linux_ebus_device *edev;

			for_each_ebusdev(edev, ebus)
				if (edev->prom_node == node)
					break;
			if (edev == NULL) {
				if (isa_chain != NULL)
					goto try_isa_clock;
				prom_printf("%s: Mostek not probed by EBUS\n",
					    __FUNCTION__);
				prom_halt();
			}

			if (!strcmp(model, "ds1287") ||
			    !strcmp(model, "m5819") ||
			    !strcmp(model, "m5819p")) {
				ds1287_regs = edev->resource[0].start;
			} else {
				mstk48t59_regs = edev->resource[0].start;
				mstk48t02_regs = mstk48t59_regs + MOSTEK_48T59_48T02;
			}
			break;
		}
		else if (isa_br != NULL) {
			struct sparc_isa_device *isadev;

try_isa_clock:
			for_each_isadev(isadev, isa_br)
				if (isadev->prom_node == node)
					break;
			if (isadev == NULL) {