/* * linux/arch/sh/kernel/rtc-mpc1211.c -- MPC-1211 on-chip RTC support * *  Copyright (C) 2002  Saito.K & Jeanne * */#include <linux/init.h>#include <linux/kernel.h>#include <linux/sched.h>#include <linux/time.h>#include <linux/mc146818rtc.h>#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/* arc/i386/kernel/time.c */unsigned long get_cmos_time(void){	unsigned int year, mon, day, hour, min, sec;	int i;	spin_lock(&rtc_lock);	/* The Linux interpretation of the CMOS clock register contents:	 * When the Update-In-Progress (UIP) flag goes from 1 to 0, the	 * RTC registers show the second which has precisely just started.	 * Let's hope other operating systems interpret the RTC the same way.	 */	/* read RTC exactly on falling edge of update flag */	for (i = 0 ; i < 1000000 ; i++)	/* may take up to 1 second... */		if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)			break;	for (i = 0 ; i < 1000000 ; i++)	/* must try at least 2.228 ms */		if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))			break;	do { /* Isn't this overkill ? UIP above should guarantee consistency */		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(&rtc_lock);	if ((year += 1900) < 1970)		year += 100;	return mktime(year, mon, day, hour, min, sec);}void mpc1211_rtc_gettimeofday(struct timeval *tv){	tv->tv_sec = get_cmos_time();	tv->tv_usec = 0;}/* arc/i386/kernel/time.c *//* * 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 int set_rtc_mmss(unsigned long nowtime){	int retval = 0;	int real_seconds, real_minutes, cmos_minutes;	unsigned char save_control, save_freq_select;	/* gets recalled with irq locally disabled */	spin_lock(&rtc_lock);	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(&rtc_lock);	return retval;}int mpc1211_rtc_settimeofday(const struct timeval *tv){	unsigned long nowtime = tv->tv_sec;	return set_rtc_mmss(nowtime);}void mpc1211_time_init(void){	rtc_get_time = mpc1211_rtc_gettimeofday;	rtc_set_time = mpc1211_rtc_settimeofday;}