nuclear@36: #include <stdio.h>
nuclear@36: #include <time.h>
nuclear@36: #include <asmops.h>
nuclear@37: #include "rtc.h"
nuclear@36: 
nuclear@36: /* CMOS I/O ports */
nuclear@36: #define PORT_CTL	0x70
nuclear@36: #define PORT_DATA	0x71
nuclear@36: 
nuclear@36: /* CMOS RTC registers */
nuclear@36: #define REG_SEC			0
nuclear@36: #define REG_ALARM_SEC	1
nuclear@36: #define REG_MIN			2
nuclear@36: #define REG_ALARM_MIN	3
nuclear@36: #define REG_HOUR		4
nuclear@36: #define REG_ALARM_HOUR	5
nuclear@36: #define REG_WEEKDAY		6
nuclear@36: #define REG_DAY			7
nuclear@36: #define REG_MONTH		8
nuclear@36: #define REG_YEAR		9
nuclear@36: #define REG_STATA		10
nuclear@36: #define REG_STATB		11
nuclear@36: #define REG_STATC		12
nuclear@36: #define REG_STATD		13
nuclear@36: 
nuclear@36: #define STATA_BUSY	(1 << 7)
nuclear@36: #define STATB_24HR	(1 << 1)
nuclear@36: #define STATB_BIN	(1 << 2)
nuclear@36: 
nuclear@36: #define HOUR_PM_BIT		(1 << 7)
nuclear@36: 
nuclear@36: #define BCD_TO_BIN(x)	((((x) >> 4) & 0xf) * 10 + ((x) & 0xf))
nuclear@36: 
nuclear@36: static void read_rtc(struct tm *tm);
nuclear@36: static int read_reg(int reg);
nuclear@36: 
nuclear@36: 
nuclear@36: void init_rtc(void)
nuclear@36: {
nuclear@36: 	struct tm tm;
nuclear@36: 
nuclear@36: 	read_rtc(&tm);
nuclear@37: 	start_time = mktime(&tm);
nuclear@37: 
nuclear@36: 	printf("System real-time clock: %s", asctime(&tm));
nuclear@36: }
nuclear@36: 
nuclear@37: 
nuclear@36: static void read_rtc(struct tm *tm)
nuclear@36: {
nuclear@36: 	int statb, pm;
nuclear@36: 
nuclear@36: 	/* wait for any clock updates to finish */
nuclear@36: 	while(read_reg(REG_STATA) & STATA_BUSY);
nuclear@36: 
nuclear@36: 	tm->tm_sec = read_reg(REG_SEC);
nuclear@36: 	tm->tm_min = read_reg(REG_MIN);
nuclear@36: 	tm->tm_hour = read_reg(REG_HOUR);
nuclear@36: 	tm->tm_mday = read_reg(REG_DAY);
nuclear@36: 	tm->tm_mon = read_reg(REG_MONTH);
nuclear@36: 	tm->tm_year = read_reg(REG_YEAR);
nuclear@36: 
nuclear@36: 	/* in 12hour mode, bit 7 means post-meridiem */
nuclear@36: 	pm = tm->tm_hour & HOUR_PM_BIT;
nuclear@36: 	tm->tm_hour &= ~HOUR_PM_BIT;
nuclear@36: 
nuclear@36: 	/* convert to binary if needed */
nuclear@36: 	statb = read_reg(REG_STATB);
nuclear@36: 	if(!(statb & STATB_BIN)) {
nuclear@36: 		tm->tm_sec = BCD_TO_BIN(tm->tm_sec);
nuclear@36: 		tm->tm_min = BCD_TO_BIN(tm->tm_min);
nuclear@36: 		tm->tm_hour = BCD_TO_BIN(tm->tm_hour);
nuclear@36: 		tm->tm_mday = BCD_TO_BIN(tm->tm_mday);
nuclear@36: 		tm->tm_mon = BCD_TO_BIN(tm->tm_mon);
nuclear@36: 		tm->tm_year = BCD_TO_BIN(tm->tm_year);
nuclear@36: 	}
nuclear@36: 
nuclear@36: 	/* make the year an offset from 1900 */
nuclear@36: 	if(tm->tm_year < 100) {
nuclear@36: 		tm->tm_year += 100;
nuclear@36: 	} else {
nuclear@36: 		tm->tm_year -= 1900;
nuclear@36: 	}
nuclear@36: 
nuclear@36: 	/* if tm_hour is in 12h mode, convert to 24h */
nuclear@36: 	if(!(statb & STATB_24HR)) {
nuclear@36: 		if(tm->tm_hour == 12) {
nuclear@36: 			tm->tm_hour = 0;
nuclear@36: 		}
nuclear@36: 		if(pm) {
nuclear@36: 			tm->tm_hour += 12;
nuclear@36: 		}
nuclear@36: 	}
nuclear@36: 
nuclear@36: 	tm->tm_mon -= 1;	/* we want months to start from 0 */
nuclear@36: }
nuclear@36: 
nuclear@36: static int read_reg(int reg)
nuclear@36: {
nuclear@36: 	unsigned char val;
nuclear@36: 	outb(reg, PORT_CTL);
nuclear@36: 	iodelay();
nuclear@36: 	inb(val, PORT_DATA);
nuclear@36: 	iodelay();
nuclear@36: 	return val;
nuclear@36: }