/* *  linux/include/asm-arm/arch-ebsa285/time.h * *  Copyright (C) 1998 Russell King. *  Copyright (C) 1998 Phil Blundell * * CATS has a real-time clock, though the evaluation board doesn't. * * Changelog: *  21-Mar-1998	RMK	Created *  27-Aug-1998	PJB	CATS support *  28-Dec-1998	APH	Made leds optional *  20-Jan-1999	RMK	Started merge of EBSA285, CATS and NetWinder *  16-Mar-1999	RMK	More support for EBSA285-like machines with RTCs in */#define RTC_PORT(x)		(rtc_base+(x))#define RTC_ALWAYS_BCD		0#include <linux/timex.h>#include <linux/init.h>#include <linux/sched.h>#include <linux/mc146818rtc.h>#include <linux/bcd.h>#include <asm/hardware.h>#include <asm/io.h>#include <asm/mach/time.h>#include "common.h"static int rtc_base;static unsigned long __init get_isa_cmos_time(void){	unsigned int year, mon, day, hour, min, sec;	int i;	// check to see if the RTC makes sense.....	if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)		return mktime(1970, 1, 1, 0, 0, 0);	/* 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);	}	if ((year += 1900) < 1970)		year += 100;	return mktime(year, mon, day, hour, min, sec);}static int set_isa_cmos_time(void){	int retval = 0;	int real_seconds, real_minutes, cmos_minutes;	unsigned char save_control, save_freq_select;	unsigned long nowtime = xtime.tv_sec;	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		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);	return retval;}void __init isa_rtc_init(void){	if (machine_is_co285() ||	    machine_is_personal_server())		/*		 * Add-in 21285s shouldn't access the RTC		 */		rtc_base = 0;	else		rtc_base = 0x70;	if (rtc_base) {		int reg_d, reg_b;		/*		 * Probe for the RTC.		 */		reg_d = CMOS_READ(RTC_REG_D);		/*		 * make sure the divider is set		 */		CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);		/*		 * Set control reg B		 *   (24 hour mode, update enabled)		 */		reg_b = CMOS_READ(RTC_REG_B) & 0x7f;		reg_b |= 2;		CMOS_WRITE(reg_b, RTC_REG_B);		if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&		    CMOS_READ(RTC_REG_B) == reg_b) {			struct timespec tv;			/*			 * We have a RTC.  Check the battery			 */			if ((reg_d & 0x80) == 0)				printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");			tv.tv_nsec = 0;			tv.tv_sec = get_isa_cmos_time();			do_settimeofday(&tv);			set_rtc = set_isa_cmos_time;		} else			rtc_base = 0;	}}