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 #define NVRAM_AS0  0x74
  33 #define NVRAM_AS1  0x75
  34 #define NVRAM_DATA 0x77
  35
  36 static int nvram_as1 = NVRAM_AS1;
  37 static int nvram_as0 = NVRAM_AS0;
  38 static int nvram_data = NVRAM_DATA;
  39
  40 long __init chrp_time_init(void)
  41 {
  42         struct device_node *rtcs;
  43         struct resource r;
  44         int base;
  45
  46         rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
  47         if (rtcs == NULL)
  48                 rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
  49         if (rtcs == NULL)
  50                 return 0;
  51         if (of_address_to_resource(rtcs, 0, &r)) {
  52                 of_node_put(rtcs);
  53                 return 0;
  54         }
  55         of_node_put(rtcs);
  56
  57         base = r.start;
  58         nvram_as1 = 0;
  59         nvram_as0 = base;
  60         nvram_data = base + 1;
  61
  62         return 0;
  63 }
  64
  65 int chrp_cmos_clock_read(int addr)
  66 {
  67         if (nvram_as1 != 0)
  68                 outb(addr>>8, nvram_as1);
  69         outb(addr, nvram_as0);
  70         return (inb(nvram_data));
  71 }
  72
  73 void chrp_cmos_clock_write(unsigned long val, int addr)
  74 {
  75         if (nvram_as1 != 0)
  76                 outb(addr>>8, nvram_as1);
  77         outb(addr, nvram_as0);
  78         outb(val, nvram_data);
  79         return;
  80 }
  81
  82 /*
  83  * Set the hardware clock. -- Cort
  84  */
  85 int chrp_set_rtc_time(struct rtc_time *tmarg)
  86 {
  87         unsigned char save_control, save_freq_select;
  88         struct rtc_time tm = *tmarg;
  89
  90         spin_lock(&rtc_lock);
  91
  92         save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  93
  94         chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
  95
  96         save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  97
  98         chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  99
 100         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 101                 tm.tm_sec = bin2bcd(tm.tm_sec);
 102                 tm.tm_min = bin2bcd(tm.tm_min);
 103                 tm.tm_hour = bin2bcd(tm.tm_hour);
 104                 tm.tm_mon = bin2bcd(tm.tm_mon);
 105                 tm.tm_mday = bin2bcd(tm.tm_mday);
 106                 tm.tm_year = bin2bcd(tm.tm_year);
 107         }
 108         chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
 109         chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
 110         chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
 111         chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
 112         chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
 113         chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
 114
 115         /* The following flags have to be released exactly in this order,
 116          * otherwise the DS12887 (popular MC146818A clone with integrated
 117          * battery and quartz) will not reset the oscillator and will not
 118          * update precisely 500 ms later. You won't find this mentioned in
 119          * the Dallas Semiconductor data sheets, but who believes data
 120          * sheets anyway ...                           -- Markus Kuhn
 121          */
 122         chrp_cmos_clock_write(save_control, RTC_CONTROL);
 123         chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
 124
 125         spin_unlock(&rtc_lock);
 126         return 0;
 127 }
 128
 129 void chrp_get_rtc_time(struct rtc_time *tm)
 130 {
 131         unsigned int year, mon, day, hour, min, sec;
 132
 133         do {
 134                 sec = chrp_cmos_clock_read(RTC_SECONDS);
 135                 min = chrp_cmos_clock_read(RTC_MINUTES);
 136                 hour = chrp_cmos_clock_read(RTC_HOURS);
 137                 day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
 138                 mon = chrp_cmos_clock_read(RTC_MONTH);
 139                 year = chrp_cmos_clock_read(RTC_YEAR);
 140         } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
 141
 142         if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 143                 sec = bcd2bin(sec);
 144                 min = bcd2bin(min);
 145                 hour = bcd2bin(hour);
 146                 day = bcd2bin(day);
 147                 mon = bcd2bin(mon);
 148                 year = bcd2bin(year);
 149         }
 150         if (year < 70)
 151                 year += 100;
 152         tm->tm_sec = sec;
 153         tm->tm_min = min;
 154         tm->tm_hour = hour;
 155         tm->tm_mday = day;
 156         tm->tm_mon = mon;
 157         tm->tm_year = year;
 158 }