time.c

来自「linux 内核源代码」· C语言 代码 · 共 603 行 · 第 1/2 页

{
	struct device_node *dp = op->node;
	const char *model = of_get_property(dp, "model", NULL);

	if (!model)
		return -ENODEV;

	if (!strcmp(model, "mk48t02")) {
		sp_clock_typ = MSTK48T02;

		/* Map the clock register io area read-only */
		mstk48t02_regs = of_ioremap(&op->resource[0], 0,
					    sizeof(struct mostek48t02),
					    "mk48t02");
		mstk48t08_regs = NULL;  /* To catch weirdness */
	} else if (!strcmp(model, "mk48t08")) {
		sp_clock_typ = MSTK48T08;
		mstk48t08_regs = of_ioremap(&op->resource[0], 0,
					    sizeof(struct mostek48t08),
					    "mk48t08");

		mstk48t02_regs = &mstk48t08_regs->regs;
	} else
		return -ENODEV;

	/* Report a low battery voltage condition. */
	if (has_low_battery())
		printk(KERN_CRIT "NVRAM: Low battery voltage!\n");

	/* Kick start the clock if it is completely stopped. */
	if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
		kick_start_clock();

	mostek_set_system_time();

	return 0;
}

static struct of_device_id clock_match[] = {
	{
		.name = "eeprom",
	},
	{},
};

static struct of_platform_driver clock_driver = {
	.match_table	= clock_match,
	.probe		= clock_probe,
	.driver		= {
		.name	= "clock",
	},
};


/* Probe for the mostek real time clock chip. */
static int __init clock_init(void)
{
	return of_register_driver(&clock_driver, &of_platform_bus_type);
}

/* Must be after subsys_initcall() so that busses are probed.  Must
 * be before device_initcall() because things like the RTC driver
 * need to see the clock registers.
 */
fs_initcall(clock_init);
#endif /* !CONFIG_SUN4 */

void __init sbus_time_init(void)
{

	BTFIXUPSET_CALL(bus_do_settimeofday, sbus_do_settimeofday, BTFIXUPCALL_NORM);
	btfixup();

	if (ARCH_SUN4)
		sun4_clock_probe();

	sparc_init_timers(timer_interrupt);
	
#ifdef CONFIG_SUN4
	if(idprom->id_machtype == (SM_SUN4 | SM_4_330)) {
		mostek_set_system_time();
	} else if(idprom->id_machtype == (SM_SUN4 | SM_4_260) ) {
		/* initialise the intersil on sun4 */
		unsigned int year, mon, day, hour, min, sec;
		int temp;
		struct intersil *iregs;

		iregs=intersil_clock;
		if(!iregs) {
			prom_printf("Something wrong, clock regs not mapped yet.\n");
			prom_halt();
		}

		intersil_intr(intersil_clock,INTERSIL_INT_100HZ);
		disable_pil_irq(10);
		intersil_stop(iregs);
		intersil_read_intr(intersil_clock, temp);

		temp = iregs->clk.int_csec;

		sec = iregs->clk.int_sec;
		min = iregs->clk.int_min;
		hour = iregs->clk.int_hour;
		day = iregs->clk.int_day;
		mon = iregs->clk.int_month;
		year = MSTK_CVT_YEAR(iregs->clk.int_year);

		enable_pil_irq(10);
		intersil_start(iregs);

		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);
		printk("%u/%u/%u %u:%u:%u\n",day,mon,year,hour,min,sec);
	}
#endif

	/* Now that OBP ticker has been silenced, it is safe to enable IRQ. */
	local_irq_enable();
}

void __init time_init(void)
{
#ifdef CONFIG_PCI
	extern void pci_time_init(void);
	if (pcic_present()) {
		pci_time_init();
		return;
	}
#endif
	sbus_time_init();
}

static inline unsigned long do_gettimeoffset(void)
{
	unsigned long val = *master_l10_counter;
	unsigned long usec = (val >> 10) & 0x1fffff;

	/* Limit hit?  */
	if (val & 0x80000000)
		usec += 1000000 / HZ;

	return usec;
}

/* Ok, my cute asm atomicity trick doesn't work anymore.
 * There are just too many variables that need to be protected
 * now (both members of xtime, et al.)
 */
void do_gettimeofday(struct timeval *tv)
{
	unsigned long flags;
	unsigned long seq;
	unsigned long usec, sec;
	unsigned long max_ntp_tick = tick_usec - tickadj;

	do {
		seq = read_seqbegin_irqsave(&xtime_lock, flags);
		usec = do_gettimeoffset();

		/*
		 * If time_adjust is negative then NTP is slowing the clock
		 * so make sure not to go into next possible interval.
		 * Better to lose some accuracy than have time go backwards..
		 */
		if (unlikely(time_adjust < 0))
			usec = min(usec, max_ntp_tick);

		sec = xtime.tv_sec;
		usec += (xtime.tv_nsec / 1000);
	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

	while (usec >= 1000000) {
		usec -= 1000000;
		sec++;
	}

	tv->tv_sec = sec;
	tv->tv_usec = usec;
}

EXPORT_SYMBOL(do_gettimeofday);

int do_settimeofday(struct timespec *tv)
{
	int ret;

	write_seqlock_irq(&xtime_lock);
	ret = bus_do_settimeofday(tv);
	write_sequnlock_irq(&xtime_lock);
	clock_was_set();
	return ret;
}

EXPORT_SYMBOL(do_settimeofday);

static int sbus_do_settimeofday(struct timespec *tv)
{
	time_t wtm_sec, sec = tv->tv_sec;
	long wtm_nsec, nsec = tv->tv_nsec;

	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
		return -EINVAL;

	/*
	 * This is revolting. We need to set "xtime" correctly. However, the
	 * value in this location is the value at the most recent update of
	 * wall time.  Discover what correction gettimeofday() would have
	 * made, and then undo it!
	 */
	nsec -= 1000 * do_gettimeoffset();

	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

	set_normalized_timespec(&xtime, sec, nsec);
	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

	ntp_clear();
	return 0;
}

/*
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you won't notice until after reboot!
 */
static int set_rtc_mmss(unsigned long nowtime)
{
	int real_seconds, real_minutes, mostek_minutes;
	struct mostek48t02 *regs = (struct mostek48t02 *)mstk48t02_regs;
	unsigned long flags;
#ifdef CONFIG_SUN4
	struct intersil *iregs = intersil_clock;
	int temp;
#endif

	/* Not having a register set can lead to trouble. */
	if (!regs) {
#ifdef CONFIG_SUN4
		if(!iregs)
		return -1;
	 	else {
			temp = iregs->clk.int_csec;

			mostek_minutes = iregs->clk.int_min;

			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) {
				intersil_stop(iregs);
				iregs->clk.int_sec=real_seconds;
				iregs->clk.int_min=real_minutes;
				intersil_start(iregs);
			} else {
				printk(KERN_WARNING
			       "set_rtc_mmss: can't update from %d to %d\n",
				       mostek_minutes, real_minutes);
				return -1;
			}
			
			return 0;
		}
#endif
	}

	spin_lock_irqsave(&mostek_lock, flags);
	/* 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;
		spin_unlock_irqrestore(&mostek_lock, flags);
		return 0;
	} else {
		spin_unlock_irqrestore(&mostek_lock, flags);
		return -1;
	}
}