arch/powerpc/platforms/chrp/time.c

   1 /*
   2  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   3  *
   4  * Adapted for PowerPC (PReP) by Gary Thomas
   5  * Modified by Cort Dougan (cort@cs.nmt.edu).
   6  * Copied and modified from arch/i386/kernel/time.c
   7  *
   8  */
   9 #include <linux/errno.h>
  10 #include <linux/sched.h>
  11 #include <linux/kernel.h>
  12 #include <linux/param.h>
  13 #include <linux/string.h>
  14 #include <linux/mm.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/time.h>
  17 #include <linux/timex.h>
  18 #include <linux/kernel_stat.h>
  19 #include <linux/mc146818rtc.h>
  20 #include <linux/init.h>
  21 #include <linux/bcd.h>
  22 #include <linux/ioport.h>
  23
  24 #include <asm/io.h>
  25 #include <asm/nvram.h>
  26 #include <asm/prom.h>
  27 #include <asm/sections.h>
  28 #include <asm/time.h>
  29
  30 extern spinlock_t rtc_lock;
  31
  32 static int nvram_as1 = NVRAM_AS1;
  33 static int nvram_as0 = NVRAM_AS0;
  34 static int nvram_data = NVRAM_DATA;
  35
  36 long __init chrp_time_init(void)
  37 {
  38         struct device_node *rtcs;
  39         struct resource r;
  40         int base;
  41
  42         rtcs = find_compatible_devices("rtc", "pnpPNP,b00");
  43         if (rtcs == NULL)
  44                 rtcs = find_compatible_devices("rtc", "ds1385-rtc");
  45         if (rtcs == NULL || of_address_to_resource(rtcs, 0, &r))
  46                 return 0;
  47
  48         base = r.start;
  49         nvram_as1 = 0;
  50         nvram_as0 = base;
  51         nvram_data = base + 1;
  52
  53         return 0;
  54 }
  55
  56 int chrp_cmos_clock_read(int addr)
  57 {
  58         if (nvram_as1 != 0)
  59                 outb(addr>>8, nvram_as1);
  60         outb(addr, nvram_as0);
  61         return (inb(nvram_data));
  62 }
  63
  64 void chrp_cmos_clock_write(unsigned long val, int addr)
  65 {
  66         if (nvram_as1 != 0)
  67                 outb(addr>>8, nvram_as1);
  68         outb(addr, nvram_as0);
  69         outb(val, nvram_data);
  70         return;
  71 }
  72
  73 /*
  74  * Set the hardware clock. -- Cort
  75  */
  76 int chrp_set_rtc_time(struct rtc_time *tmarg)
  77 {
  78         unsigned char save_control, save_freq_select;
  79         struct rtc_time tm = *tmarg;
  80
  81         spin_lock(&rtc_lock);
  82
  83         save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  84
  85         chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
  86
  87         save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  88
  89         chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  90
  91         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
  92                 BIN_TO_BCD(tm.tm_sec);
  93                 BIN_TO_BCD(tm.tm_min);
  94                 BIN_TO_BCD(tm.tm_hour);
  95                 BIN_TO_BCD(tm.tm_mon);
  96                 BIN_TO_BCD(tm.tm_mday);
  97                 BIN_TO_BCD(tm.tm_year);
  98         }
  99         chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
 100         chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
 101         chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
 102         chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
 103         chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
 104         chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
 105
 106         /* The following flags have to be released exactly in this order,
 107          * otherwise the DS12887 (popular MC146818A clone with integrated
 108          * battery and quartz) will not reset the oscillator and will not
 109          * update precisely 500 ms later. You won't find this mentioned in
 110          * the Dallas Semiconductor data sheets, but who believes data
 111          * sheets anyway ...                           -- Markus Kuhn
 112          */
 113         chrp_cmos_clock_write(save_control, RTC_CONTROL);
 114         chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
 115
 116         spin_unlock(&rtc_lock);
 117         return 0;
 118 }
 119
 120 void chrp_get_rtc_time(struct rtc_time *tm)
 121 {
 122         unsigned int year, mon, day, hour, min, sec;
 123
 124         do {
 125                 sec = chrp_cmos_clock_read(RTC_SECONDS);
 126                 min = chrp_cmos_clock_read(RTC_MINUTES);
 127                 hour = chrp_cmos_clock_read(RTC_HOURS);
 128                 day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
 129                 mon = chrp_cmos_clock_read(RTC_MONTH);
 130                 year = chrp_cmos_clock_read(RTC_YEAR);
 131         } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
 132
 133         if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 134                 BCD_TO_BIN(sec);
 135                 BCD_TO_BIN(min);
 136                 BCD_TO_BIN(hour);
 137                 BCD_TO_BIN(day);
 138                 BCD_TO_BIN(mon);
 139                 BCD_TO_BIN(year);
 140         }
 141         if (year < 70)
 142                 year += 100;
 143         tm->tm_sec = sec;
 144         tm->tm_min = min;
 145         tm->tm_hour = hour;
 146         tm->tm_mday = day;
 147         tm->tm_mon = mon;
 148         tm->tm_year = year;
 149 }