/*

   *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   *  Copyright (C) 2000, 2003  Maciej W. Rozycki
   *
   * This file contains the time handling details for PC-style clocks as
   * found in some MIPS systems.
   *
   */
  #include <linux/bcd.h>

  #include <linux/init.h>

  #include <linux/mc146818rtc.h>

  #include <linux/param.h>

  #include <asm/cpu-features.h>
  #include <asm/ds1287.h>
  #include <asm/time.h>

  #include <asm/dec/interrupts.h>
  #include <asm/dec/ioasic.h>

  #include <asm/dec/machtype.h>

  void read_persistent_clock(struct timespec *ts)

  {
  	unsigned int year, mon, day, hour, min, sec, real_year;

  	unsigned long flags;

  	spin_lock_irqsave(&rtc_lock, flags);

  	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);

  		/*
  		 * The PROM will reset the year to either '72 or '73.
  		 * Therefore we store the real year separately, in one
  		 * of unused BBU RAM locations.
  		 */
  		real_year = CMOS_READ(RTC_DEC_YEAR);

  	} while (sec != CMOS_READ(RTC_SECONDS));

  
  	spin_unlock_irqrestore(&rtc_lock, flags);

  	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {

  		sec = bcd2bin(sec);
  		min = bcd2bin(min);
  		hour = bcd2bin(hour);
  		day = bcd2bin(day);
  		mon = bcd2bin(mon);
  		year = bcd2bin(year);

  	}

  	year += real_year - 72 + 2000;

  	ts->tv_sec = mktime(year, mon, day, hour, min, sec);
  	ts->tv_nsec = 0;

  }
  
  /*

   * In order to set the CMOS clock precisely, rtc_mips_set_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 Dallas
   * DS1287 data sheet for details.
   */

  int rtc_mips_set_mmss(unsigned long nowtime)

  {
  	int retval = 0;
  	int real_seconds, real_minutes, cmos_minutes;
  	unsigned char save_control, save_freq_select;

  	/* irq are locally disabled here */
  	spin_lock(&rtc_lock);

  	/* tell the clock it's being set */
  	save_control = CMOS_READ(RTC_CONTROL);
  	CMOS_WRITE((save_control | RTC_SET), RTC_CONTROL);
  
  	/* stop and reset prescaler */
  	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
  	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)

  		cmos_minutes = bcd2bin(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) {

  			real_seconds = bin2bcd(real_seconds);
  			real_minutes = bin2bcd(real_minutes);

  		}
  		CMOS_WRITE(real_seconds, RTC_SECONDS);
  		CMOS_WRITE(real_minutes, RTC_MINUTES);
  	} else {

  		printk_once(KERN_NOTICE

  		       "set_rtc_mmss: can't update from %d to %d
  ",
  		       cmos_minutes, real_minutes);
  		retval = -1;
  	}
  
  	/* The following flags have to be released exactly in this order,
  	 * otherwise the DS1287 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;
  }

  void __init plat_time_init(void)

  {

  	u32 start, end;
  	int i = HZ / 10;

  	/* Set up the rate of periodic DS1287 interrupts. */
  	ds1287_set_base_clock(HZ);

  	if (cpu_has_counter) {
  		while (!ds1287_timer_state())
  			;

  		start = read_c0_count();

  		while (i--)
  			while (!ds1287_timer_state())
  				;
  
  		end = read_c0_count();

  		mips_hpt_frequency = (end - start) * 10;
  		printk(KERN_INFO "MIPS counter frequency %dHz
  ",
  			mips_hpt_frequency);
  	} else if (IOASIC)

  		/* For pre-R4k systems we use the I/O ASIC's counter.  */

  		dec_ioasic_clocksource_init();

  	ds1287_clockevent_init(dec_interrupt[DEC_IRQ_RTC]);

  }