| /* |
| * 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/bcd.h> |
| #include <linux/mc146818rtc.h> |
| |
| unsigned long get_cmos_time(void) |
| { |
| unsigned int year, mon, day, hour, min, sec; |
| |
| spin_lock(&rtc_lock); |
| |
| 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(&rtc_lock); |
| |
| year += 1900; |
| if (year < 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; |
| } |
| |