165 lines
4.1 KiB
C
165 lines
4.1 KiB
C
/*
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* arch/arm/mach-footbridge/include/mach/time.h
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*
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* Copyright (C) 1998 Russell King.
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* Copyright (C) 1998 Phil Blundell
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*
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* CATS has a real-time clock, though the evaluation board doesn't.
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*
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* Changelog:
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* 21-Mar-1998 RMK Created
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* 27-Aug-1998 PJB CATS support
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* 28-Dec-1998 APH Made leds optional
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* 20-Jan-1999 RMK Started merge of EBSA285, CATS and NetWinder
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* 16-Mar-1999 RMK More support for EBSA285-like machines with RTCs in
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*/
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#define RTC_PORT(x) (rtc_base+(x))
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#define RTC_ALWAYS_BCD 0
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#include <linux/timex.h>
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#include <linux/init.h>
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#include <linux/sched.h>
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#include <linux/mc146818rtc.h>
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#include <linux/bcd.h>
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#include <linux/io.h>
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#include <mach/hardware.h>
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#include <asm/mach/time.h>
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#include "common.h"
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static int rtc_base;
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static unsigned long __init get_isa_cmos_time(void)
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{
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unsigned int year, mon, day, hour, min, sec;
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// check to see if the RTC makes sense.....
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if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)
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return mktime(1970, 1, 1, 0, 0, 0);
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do {
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sec = CMOS_READ(RTC_SECONDS);
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min = CMOS_READ(RTC_MINUTES);
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hour = CMOS_READ(RTC_HOURS);
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day = CMOS_READ(RTC_DAY_OF_MONTH);
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mon = CMOS_READ(RTC_MONTH);
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year = CMOS_READ(RTC_YEAR);
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} while (sec != CMOS_READ(RTC_SECONDS));
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if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
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BCD_TO_BIN(sec);
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BCD_TO_BIN(min);
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BCD_TO_BIN(hour);
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BCD_TO_BIN(day);
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BCD_TO_BIN(mon);
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BCD_TO_BIN(year);
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}
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if ((year += 1900) < 1970)
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year += 100;
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return mktime(year, mon, day, hour, min, sec);
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}
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static int set_isa_cmos_time(void)
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{
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int retval = 0;
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int real_seconds, real_minutes, cmos_minutes;
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unsigned char save_control, save_freq_select;
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unsigned long nowtime = xtime.tv_sec;
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save_control = CMOS_READ(RTC_CONTROL); /* tell the clock it's being set */
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CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
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save_freq_select = CMOS_READ(RTC_FREQ_SELECT); /* stop and reset prescaler */
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CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
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cmos_minutes = CMOS_READ(RTC_MINUTES);
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if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
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BCD_TO_BIN(cmos_minutes);
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/*
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* since we're only adjusting minutes and seconds,
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* don't interfere with hour overflow. This avoids
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* messing with unknown time zones but requires your
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* RTC not to be off by more than 15 minutes
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*/
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real_seconds = nowtime % 60;
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real_minutes = nowtime / 60;
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if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)
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real_minutes += 30; /* correct for half hour time zone */
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real_minutes %= 60;
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if (abs(real_minutes - cmos_minutes) < 30) {
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if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
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BIN_TO_BCD(real_seconds);
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BIN_TO_BCD(real_minutes);
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}
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CMOS_WRITE(real_seconds,RTC_SECONDS);
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CMOS_WRITE(real_minutes,RTC_MINUTES);
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} else
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retval = -1;
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/* The following flags have to be released exactly in this order,
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* otherwise the DS12887 (popular MC146818A clone with integrated
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* battery and quartz) will not reset the oscillator and will not
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* update precisely 500 ms later. You won't find this mentioned in
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* the Dallas Semiconductor data sheets, but who believes data
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* sheets anyway ... -- Markus Kuhn
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*/
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CMOS_WRITE(save_control, RTC_CONTROL);
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CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
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return retval;
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}
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void __init isa_rtc_init(void)
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{
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if (machine_is_personal_server())
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/*
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* Add-in 21285s shouldn't access the RTC
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*/
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rtc_base = 0;
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else
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rtc_base = 0x70;
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if (rtc_base) {
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int reg_d, reg_b;
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/*
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* Probe for the RTC.
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*/
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reg_d = CMOS_READ(RTC_REG_D);
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/*
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* make sure the divider is set
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*/
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CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);
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/*
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* Set control reg B
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* (24 hour mode, update enabled)
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*/
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reg_b = CMOS_READ(RTC_REG_B) & 0x7f;
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reg_b |= 2;
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CMOS_WRITE(reg_b, RTC_REG_B);
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if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&
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CMOS_READ(RTC_REG_B) == reg_b) {
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struct timespec tv;
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/*
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* We have a RTC. Check the battery
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*/
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if ((reg_d & 0x80) == 0)
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printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");
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tv.tv_nsec = 0;
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tv.tv_sec = get_isa_cmos_time();
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do_settimeofday(&tv);
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set_rtc = set_isa_cmos_time;
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} else
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rtc_base = 0;
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}
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}
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