arch/powerpc/platforms/chrp/time.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 1991, 1992, 1995  Linus Torvalds
   4  *
   5  * Adapted for PowerPC (PReP) by Gary Thomas
   6  * Modified by Cort Dougan (cort@cs.nmt.edu).
   7  * Copied and modified from arch/i386/kernel/time.c
   8  *
   9  */
  10 #include <linux/errno.h>
  11 #include <linux/sched.h>
  12 #include <linux/kernel.h>
  13 #include <linux/param.h>
  14 #include <linux/string.h>
  15 #include <linux/mm.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/time.h>
  18 #include <linux/timex.h>
  19 #include <linux/kernel_stat.h>
  20 #include <linux/mc146818rtc.h>
  21 #include <linux/init.h>
  22 #include <linux/bcd.h>
  23 #include <linux/ioport.h>
  24
  25 #include <asm/io.h>
  26 #include <asm/nvram.h>
  27 #include <asm/prom.h>
  28 #include <asm/sections.h>
  29 #include <asm/time.h>
  30
  31 extern spinlock_t rtc_lock;
  32
  33 #define NVRAM_AS0  0x74
  34 #define NVRAM_AS1  0x75
  35 #define NVRAM_DATA 0x77
  36
  37 static int nvram_as1 = NVRAM_AS1;
  38 static int nvram_as0 = NVRAM_AS0;
  39 static int nvram_data = NVRAM_DATA;
  40
  41 long __init chrp_time_init(void)
  42 {
  43         struct device_node *rtcs;
  44         struct resource r;
  45         int base;
  46
  47         rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
  48         if (rtcs == NULL)
  49                 rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
  50         if (rtcs == NULL)
  51                 return 0;
  52         if (of_address_to_resource(rtcs, 0, &r)) {
  53                 of_node_put(rtcs);
  54                 return 0;
  55         }
  56         of_node_put(rtcs);
  57
  58         base = r.start;
  59         nvram_as1 = 0;
  60         nvram_as0 = base;
  61         nvram_data = base + 1;
  62
  63         return 0;
  64 }
  65
  66 int chrp_cmos_clock_read(int addr)
  67 {
  68         if (nvram_as1 != 0)
  69                 outb(addr>>8, nvram_as1);
  70         outb(addr, nvram_as0);
  71         return (inb(nvram_data));
  72 }
  73
  74 void chrp_cmos_clock_write(unsigned long val, int addr)
  75 {
  76         if (nvram_as1 != 0)
  77                 outb(addr>>8, nvram_as1);
  78         outb(addr, nvram_as0);
  79         outb(val, nvram_data);
  80         return;
  81 }
  82
  83 /*
  84  * Set the hardware clock. -- Cort
  85  */
  86 int chrp_set_rtc_time(struct rtc_time *tmarg)
  87 {
  88         unsigned char save_control, save_freq_select;
  89         struct rtc_time tm = *tmarg;
  90
  91         spin_lock(&rtc_lock);
  92
  93         save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  94
  95         chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
  96
  97         save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  98
  99         chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 100
 101         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 102                 tm.tm_sec = bin2bcd(tm.tm_sec);
 103                 tm.tm_min = bin2bcd(tm.tm_min);
 104                 tm.tm_hour = bin2bcd(tm.tm_hour);
 105                 tm.tm_mon = bin2bcd(tm.tm_mon);
 106                 tm.tm_mday = bin2bcd(tm.tm_mday);
 107                 tm.tm_year = bin2bcd(tm.tm_year);
 108         }
 109         chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
 110         chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
 111         chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
 112         chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
 113         chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
 114         chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
 115
 116         /* The following flags have to be released exactly in this order,
 117          * otherwise the DS12887 (popular MC146818A clone with integrated
 118          * battery and quartz) will not reset the oscillator and will not
 119          * update precisely 500 ms later. You won't find this mentioned in
 120          * the Dallas Semiconductor data sheets, but who believes data
 121          * sheets anyway ...                           -- Markus Kuhn
 122          */
 123         chrp_cmos_clock_write(save_control, RTC_CONTROL);
 124         chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
 125
 126         spin_unlock(&rtc_lock);
 127         return 0;
 128 }
 129
 130 void chrp_get_rtc_time(struct rtc_time *tm)
 131 {
 132         unsigned int year, mon, day, hour, min, sec;
 133
 134         do {
 135                 sec = chrp_cmos_clock_read(RTC_SECONDS);
 136                 min = chrp_cmos_clock_read(RTC_MINUTES);
 137                 hour = chrp_cmos_clock_read(RTC_HOURS);
 138                 day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
 139                 mon = chrp_cmos_clock_read(RTC_MONTH);
 140                 year = chrp_cmos_clock_read(RTC_YEAR);
 141         } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
 142
 143         if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 144                 sec = bcd2bin(sec);
 145                 min = bcd2bin(min);
 146                 hour = bcd2bin(hour);
 147                 day = bcd2bin(day);
 148                 mon = bcd2bin(mon);
 149                 year = bcd2bin(year);
 150         }
 151         if (year < 70)
 152                 year += 100;
 153         tm->tm_sec = sec;
 154         tm->tm_min = min;
 155         tm->tm_hour = hour;
 156         tm->tm_mday = day;
 157         tm->tm_mon = mon;
 158         tm->tm_year = year;
 159 }