[linux.git] / include / asm-mips / mc146818-time.h

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Machine dependent access functions for RTC registers.
 */
#ifndef __ASM_MC146818_TIME_H
#define __ASM_MC146818_TIME_H

#include <linux/bcd.h>
#include <linux/mc146818rtc.h>
#include <linux/time.h>

/*
 * For check timing call set_rtc_mmss() 500ms; used in timer interrupt.
 */
#define USEC_AFTER	500000
#define USEC_BEFORE	500000

/*
 * In order to set the CMOS clock precisely, set_rtc_mmss has to be
 * called 500 ms after the second nowtime has started, because when
 * nowtime is written into the registers of the CMOS clock, it will
 * jump to the next second precisely 500 ms later. Check the Motorola
 * MC146818A or Dallas DS12887 data sheet for details.
 *
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you'll only notice that after reboot!
 */
static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
{
	int real_seconds, real_minutes, cmos_minutes;
	unsigned char save_control, save_freq_select;
	int retval = 0;
	unsigned long flags;

	spin_lock_irqsave(&rtc_lock, flags);
	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);

	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

	cmos_minutes = CMOS_READ(RTC_MINUTES);
	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
		BCD_TO_BIN(cmos_minutes);

	/*
	 * 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 - cmos_minutes) + 15)/30) & 1)
		real_minutes += 30;		/* correct for half hour time zone */
	real_minutes %= 60;

	if (abs(real_minutes - cmos_minutes) < 30) {
		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
			BIN_TO_BCD(real_seconds);
			BIN_TO_BCD(real_minutes);
		}
		CMOS_WRITE(real_seconds, RTC_SECONDS);
		CMOS_WRITE(real_minutes, RTC_MINUTES);
	} else {
		printk(KERN_WARNING
		       "set_rtc_mmss: can't update from %d to %d\n",
		       cmos_minutes, real_minutes);
		retval = -1;
	}

	/* The following flags have to be released exactly in this order,
	 * otherwise the DS12887 (popular MC146818A clone with integrated
	 * battery and quartz) will not reset the oscillator and will not
	 * update precisely 500 ms later. You won't find this mentioned in
	 * the Dallas Semiconductor data sheets, but who believes data
	 * sheets anyway ...                           -- Markus Kuhn
	 */
	CMOS_WRITE(save_control, RTC_CONTROL);
	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
	spin_unlock_irqrestore(&rtc_lock, flags);

	return retval;
}

static inline unsigned long mc146818_get_cmos_time(void)
{
	unsigned int year, mon, day, hour, min, sec;
	unsigned long flags;

	spin_lock_irqsave(&rtc_lock, flags);

	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);
	}
	spin_unlock_irqrestore(&rtc_lock, flags);
	year = mc146818_decode_year(year);

	return mktime(year, mon, day, hour, min, sec);
}

#endif /* __ASM_MC146818_TIME_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This file is subject to the terms and conditions of the GNU General Public
	3	* License. See the file "COPYING" in the main directory of this archive
	4	* for more details.
	5	*
	6	* Machine dependent access functions for RTC registers.
	7	*/
	8	#ifndef __ASM_MC146818_TIME_H
	9	#define __ASM_MC146818_TIME_H
	10
	11	#include <linux/bcd.h>
	12	#include <linux/mc146818rtc.h>
	13	#include <linux/time.h>
	14
	15	/*
	16	* For check timing call set_rtc_mmss() 500ms; used in timer interrupt.
	17	*/
	18	#define USEC_AFTER 500000
	19	#define USEC_BEFORE 500000
	20
	21	/*
	22	* In order to set the CMOS clock precisely, set_rtc_mmss has to be
	23	* called 500 ms after the second nowtime has started, because when
	24	* nowtime is written into the registers of the CMOS clock, it will
	25	* jump to the next second precisely 500 ms later. Check the Motorola
	26	* MC146818A or Dallas DS12887 data sheet for details.
	27	*
	28	* BUG: This routine does not handle hour overflow properly; it just
	29	* sets the minutes. Usually you'll only notice that after reboot!
	30	*/
	31	static inline int mc146818_set_rtc_mmss(unsigned long nowtime)
	32	{
	33	int real_seconds, real_minutes, cmos_minutes;
	34	unsigned char save_control, save_freq_select;
	35	int retval = 0;
53c2df2f	36	unsigned long flags;
1da177e4	37
53c2df2f	38	spin_lock_irqsave(&rtc_lock, flags);
1da177e4 LT	39	save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
	40	CMOS_WRITE((save_control\|RTC_SET), RTC_CONTROL);
	41
	42	save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
	43	CMOS_WRITE((save_freq_select\|RTC_DIV_RESET2), RTC_FREQ_SELECT);
	44
	45	cmos_minutes = CMOS_READ(RTC_MINUTES);
	46	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD)
	47	BCD_TO_BIN(cmos_minutes);
	48
	49	/*
	50	* since we're only adjusting minutes and seconds,
	51	* don't interfere with hour overflow. This avoids
	52	* messing with unknown time zones but requires your
	53	* RTC not to be off by more than 15 minutes
	54	*/
	55	real_seconds = nowtime % 60;
	56	real_minutes = nowtime / 60;
	57	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
	58	real_minutes += 30; /* correct for half hour time zone */
	59	real_minutes %= 60;
	60
	61	if (abs(real_minutes - cmos_minutes) < 30) {
	62	if (!(save_control & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD) {
	63	BIN_TO_BCD(real_seconds);
	64	BIN_TO_BCD(real_minutes);
	65	}
21a151d8 RB	66	CMOS_WRITE(real_seconds, RTC_SECONDS);
21a151d8 RB	67	CMOS_WRITE(real_minutes, RTC_MINUTES);
1da177e4 LT	68	} else {
	69	printk(KERN_WARNING
	70	"set_rtc_mmss: can't update from %d to %d\n",
	71	cmos_minutes, real_minutes);
	72	retval = -1;
	73	}
	74
	75	/* The following flags have to be released exactly in this order,
	76	* otherwise the DS12887 (popular MC146818A clone with integrated
	77	* battery and quartz) will not reset the oscillator and will not
	78	* update precisely 500 ms later. You won't find this mentioned in
	79	* the Dallas Semiconductor data sheets, but who believes data
	80	* sheets anyway ... -- Markus Kuhn
	81	*/
	82	CMOS_WRITE(save_control, RTC_CONTROL);
	83	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
53c2df2f	84	spin_unlock_irqrestore(&rtc_lock, flags);
1da177e4 LT	85
	86	return retval;
	87	}
	88
	89	static inline unsigned long mc146818_get_cmos_time(void)
	90	{
	91	unsigned int year, mon, day, hour, min, sec;
53c2df2f	92	unsigned long flags;
1da177e4	93
53c2df2f	94	spin_lock_irqsave(&rtc_lock, flags);
da2468b6 MM	95
da2468b6 MM	96	do {
1da177e4 LT	97	sec = CMOS_READ(RTC_SECONDS);
	98	min = CMOS_READ(RTC_MINUTES);
	99	hour = CMOS_READ(RTC_HOURS);
	100	day = CMOS_READ(RTC_DAY_OF_MONTH);
	101	mon = CMOS_READ(RTC_MONTH);
	102	year = CMOS_READ(RTC_YEAR);
	103	} while (sec != CMOS_READ(RTC_SECONDS));
	104
	105	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) \|\| RTC_ALWAYS_BCD) {
	106	BCD_TO_BIN(sec);
	107	BCD_TO_BIN(min);
	108	BCD_TO_BIN(hour);
	109	BCD_TO_BIN(day);
	110	BCD_TO_BIN(mon);
	111	BCD_TO_BIN(year);
	112	}
53c2df2f	113	spin_unlock_irqrestore(&rtc_lock, flags);
1da177e4 LT	114	year = mc146818_decode_year(year);
	115
	116	return mktime(year, mon, day, hour, min, sec);
	117	}
	118
	119	#endif /* __ASM_MC146818_TIME_H */