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 = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
  43         if (rtcs == NULL)
  44                 rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
  45         if (rtcs == NULL)
  46                 return 0;
  47         if (of_address_to_resource(rtcs, 0, &r)) {
  48                 of_node_put(rtcs);
  49                 return 0;
  50         }
  51         of_node_put(rtcs);
  52
  53         base = r.start;
  54         nvram_as1 = 0;
  55         nvram_as0 = base;
  56         nvram_data = base + 1;
  57
  58         return 0;
  59 }
  60
  61 int chrp_cmos_clock_read(int addr)
  62 {
  63         if (nvram_as1 != 0)
  64                 outb(addr>>8, nvram_as1);
  65         outb(addr, nvram_as0);
  66         return (inb(nvram_data));
  67 }
  68
  69 void chrp_cmos_clock_write(unsigned long val, int addr)
  70 {
  71         if (nvram_as1 != 0)
  72                 outb(addr>>8, nvram_as1);
  73         outb(addr, nvram_as0);
  74         outb(val, nvram_data);
  75         return;
  76 }
  77
  78 /*
  79  * Set the hardware clock. -- Cort
  80  */
  81 int chrp_set_rtc_time(struct rtc_time *tmarg)
  82 {
  83         unsigned char save_control, save_freq_select;
  84         struct rtc_time tm = *tmarg;
  85
  86         spin_lock(&rtc_lock);
  87
  88         save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  89
  90         chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
  91
  92         save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  93
  94         chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  95
  96         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
  97                 tm.tm_sec = bin2bcd(tm.tm_sec);
  98                 tm.tm_min = bin2bcd(tm.tm_min);
  99                 tm.tm_hour = bin2bcd(tm.tm_hour);
 100                 tm.tm_mon = bin2bcd(tm.tm_mon);
 101                 tm.tm_mday = bin2bcd(tm.tm_mday);
 102                 tm.tm_year = bin2bcd(tm.tm_year);
 103         }
 104         chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
 105         chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
 106         chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
 107         chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
 108         chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
 109         chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
 110
 111         /* The following flags have to be released exactly in this order,
 112          * otherwise the DS12887 (popular MC146818A clone with integrated
 113          * battery and quartz) will not reset the oscillator and will not
 114          * update precisely 500 ms later. You won't find this mentioned in
 115          * the Dallas Semiconductor data sheets, but who believes data
 116          * sheets anyway ...                           -- Markus Kuhn
 117          */
 118         chrp_cmos_clock_write(save_control, RTC_CONTROL);
 119         chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
 120
 121         spin_unlock(&rtc_lock);
 122         return 0;
 123 }
 124
 125 void chrp_get_rtc_time(struct rtc_time *tm)
 126 {
 127         unsigned int year, mon, day, hour, min, sec;
 128
 129         do {
 130                 sec = chrp_cmos_clock_read(RTC_SECONDS);
 131                 min = chrp_cmos_clock_read(RTC_MINUTES);
 132                 hour = chrp_cmos_clock_read(RTC_HOURS);
 133                 day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
 134                 mon = chrp_cmos_clock_read(RTC_MONTH);
 135                 year = chrp_cmos_clock_read(RTC_YEAR);
 136         } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
 137
 138         if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 139                 sec = bcd2bin(sec);
 140                 min = bcd2bin(min);
 141                 hour = bcd2bin(hour);
 142                 day = bcd2bin(day);
 143                 mon = bcd2bin(mon);
 144                 year = bcd2bin(year);
 145         }
 146         if (year < 70)
 147                 year += 100;
 148         tm->tm_sec = sec;
 149         tm->tm_min = min;
 150         tm->tm_hour = hour;
 151         tm->tm_mday = day;
 152         tm->tm_mon = mon;
 153         tm->tm_year = year;
 154 }