LXR linux/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#include <platforms/chrp/chrp.h>
  32
  33extern spinlock_t rtc_lock;
  34
  35#define NVRAM_AS0  0x74
  36#define NVRAM_AS1  0x75
  37#define NVRAM_DATA 0x77
  38
  39static int nvram_as1 = NVRAM_AS1;
  40static int nvram_as0 = NVRAM_AS0;
  41static int nvram_data = NVRAM_DATA;
  42
  43long __init chrp_time_init(void)
  44{
  45        struct device_node *rtcs;
  46        struct resource r;
  47        int base;
  48
  49        rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
  50        if (rtcs == NULL)
  51                rtcs = of_find_compatible_node(NULL, "rtc", "ds1385-rtc");
  52        if (rtcs == NULL)
  53                return 0;
  54        if (of_address_to_resource(rtcs, 0, &r)) {
  55                of_node_put(rtcs);
  56                return 0;
  57        }
  58        of_node_put(rtcs);
  59
  60        base = r.start;
  61        nvram_as1 = 0;
  62        nvram_as0 = base;
  63        nvram_data = base + 1;
  64
  65        return 0;
  66}
  67
  68static int chrp_cmos_clock_read(int addr)
  69{
  70        if (nvram_as1 != 0)
  71                outb(addr>>8, nvram_as1);
  72        outb(addr, nvram_as0);
  73        return (inb(nvram_data));
  74}
  75
  76static void chrp_cmos_clock_write(unsigned long val, int addr)
  77{
  78        if (nvram_as1 != 0)
  79                outb(addr>>8, nvram_as1);
  80        outb(addr, nvram_as0);
  81        outb(val, nvram_data);
  82        return;
  83}
  84
  85/*
  86 * Set the hardware clock. -- Cort
  87 */
  88int chrp_set_rtc_time(struct rtc_time *tmarg)
  89{
  90        unsigned char save_control, save_freq_select;
  91        struct rtc_time tm = *tmarg;
  92
  93        spin_lock(&rtc_lock);
  94
  95        save_control = chrp_cmos_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  96
  97        chrp_cmos_clock_write((save_control|RTC_SET), RTC_CONTROL);
  98
  99        save_freq_select = chrp_cmos_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
 100
 101        chrp_cmos_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 102
 103        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 104                tm.tm_sec = bin2bcd(tm.tm_sec);
 105                tm.tm_min = bin2bcd(tm.tm_min);
 106                tm.tm_hour = bin2bcd(tm.tm_hour);
 107                tm.tm_mon = bin2bcd(tm.tm_mon);
 108                tm.tm_mday = bin2bcd(tm.tm_mday);
 109                tm.tm_year = bin2bcd(tm.tm_year);
 110        }
 111        chrp_cmos_clock_write(tm.tm_sec,RTC_SECONDS);
 112        chrp_cmos_clock_write(tm.tm_min,RTC_MINUTES);
 113        chrp_cmos_clock_write(tm.tm_hour,RTC_HOURS);
 114        chrp_cmos_clock_write(tm.tm_mon,RTC_MONTH);
 115        chrp_cmos_clock_write(tm.tm_mday,RTC_DAY_OF_MONTH);
 116        chrp_cmos_clock_write(tm.tm_year,RTC_YEAR);
 117
 118        /* The following flags have to be released exactly in this order,
 119         * otherwise the DS12887 (popular MC146818A clone with integrated
 120         * battery and quartz) will not reset the oscillator and will not
 121         * update precisely 500 ms later. You won't find this mentioned in
 122         * the Dallas Semiconductor data sheets, but who believes data
 123         * sheets anyway ...                           -- Markus Kuhn
 124         */
 125        chrp_cmos_clock_write(save_control, RTC_CONTROL);
 126        chrp_cmos_clock_write(save_freq_select, RTC_FREQ_SELECT);
 127
 128        spin_unlock(&rtc_lock);
 129        return 0;
 130}
 131
 132void chrp_get_rtc_time(struct rtc_time *tm)
 133{
 134        unsigned int year, mon, day, hour, min, sec;
 135
 136        do {
 137                sec = chrp_cmos_clock_read(RTC_SECONDS);
 138                min = chrp_cmos_clock_read(RTC_MINUTES);
 139                hour = chrp_cmos_clock_read(RTC_HOURS);
 140                day = chrp_cmos_clock_read(RTC_DAY_OF_MONTH);
 141                mon = chrp_cmos_clock_read(RTC_MONTH);
 142                year = chrp_cmos_clock_read(RTC_YEAR);
 143        } while (sec != chrp_cmos_clock_read(RTC_SECONDS));
 144
 145        if (!(chrp_cmos_clock_read(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 146                sec = bcd2bin(sec);
 147                min = bcd2bin(min);
 148                hour = bcd2bin(hour);
 149                day = bcd2bin(day);
 150                mon = bcd2bin(mon);
 151                year = bcd2bin(year);
 152        }
 153        if (year < 70)
 154                year += 100;
 155        tm->tm_sec = sec;
 156        tm->tm_min = min;
 157        tm->tm_hour = hour;
 158        tm->tm_mday = day;
 159        tm->tm_mon = mon;
 160        tm->tm_year = year;
 161}
 162