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time.c

/*
 *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
 *
 * Adapted for PowerPC (PReP) by Gary Thomas
 * Modified by Cort Dougan (cort@cs.nmt.edu).
 * Copied and modified from arch/i386/kernel/time.c
 *
 */
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/kernel_stat.h>
#include <linux/mc146818rtc.h>
#include <linux/init.h>
#include <linux/bcd.h>
#include <linux/ioport.h>

#include <asm/io.h>
#include <asm/nvram.h>
#include <asm/prom.h>
#include <asm/sections.h>
#include <asm/time.h>

extern spinlock_t rtc_lock;

static int nvram_as1 = NVRAM_AS1;
static int nvram_as0 = NVRAM_AS0;
static int nvram_data = NVRAM_DATA;

long __init chrp_time_init(void)
{
      struct device_node *rtcs;
      struct resource r;
      int base;

      rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
      if (rtcs == NULL)
            rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
      if (rtcs == NULL)
            return 0;
      if (of_address_to_resource(rtcs, 0, &r)) {
            of_node_put(rtcs);
            return 0;
      }
      of_node_put(rtcs);

      base = r.start;
      nvram_as1 = 0;
      nvram_as0 = base;
      nvram_data = base + 1;

      return 0;
}

int chrp_cmos_clock_read(int addr)
{
      if (nvram_as1 != 0)
            outb(addr>>8, nvram_as1);
      outb(addr, nvram_as0);
      return (inb(nvram_data));
}

void chrp_cmos_clock_write(unsigned long val, int addr)
{
      if (nvram_as1 != 0)
            outb(addr>>8, nvram_as1);
      outb(addr, nvram_as0);
      outb(val, nvram_data);
      return;
}

/*
 * Set the hardware clock. -- Cort
 */
int chrp_set_rtc_time(struct rtc_time *tmarg)
{
      unsigned char save_control, save_freq_select;
      struct rtc_time tm = *tmarg;

      spin_lock(&rtc_lock);

      save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */

      chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);

      save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */

      chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

      if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
            tm.tm_sec = bin2bcd(tm.tm_sec);
            tm.tm_min = bin2bcd(tm.tm_min);
            tm.tm_hour = bin2bcd(tm.tm_hour);
            tm.tm_mon = bin2bcd(tm.tm_mon);
            tm.tm_mday = bin2bcd(tm.tm_mday);
            tm.tm_year = bin2bcd(tm.tm_year);
      }
      chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
      chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
      chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
      chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
      chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
      chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);

      /* 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
       */
      chrp_cmos_clock_write(save_control, RTC_CONTROL);
      chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);

      spin_unlock(&rtc_lock);
      return 0;
}

void chrp_get_rtc_time(struct rtc_time *tm)
{
      unsigned int year, mon, day, hour, min, sec;

      do {
            sec = chrp_cmos_clock_read(RTC_SECONDS);
            min = chrp_cmos_clock_read(RTC_MINUTES);
            hour = chrp_cmos_clock_read(RTC_HOURS);
            day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
            mon = chrp_cmos_clock_read(RTC_MONTH);
            year = chrp_cmos_clock_read(RTC_YEAR);
      } while (sec != chrp_cmos_clock_read(RTC_SECONDS));

      if (!(chrp_cmos_clock_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);
      }
      if (year < 70)
            year += 100;
      tm->tm_sec = sec;
      tm->tm_min = min;
      tm->tm_hour = hour;
      tm->tm_mday = day;
      tm->tm_mon = mon;
      tm->tm_year = year;
}

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