LXR linux/arch/powerpc/platforms/maple/time.c

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org),
   4 *                     IBM Corp. 
   5 */
   6
   7#undef DEBUG
   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/init.h>
  16#include <linux/time.h>
  17#include <linux/adb.h>
  18#include <linux/pmu.h>
  19#include <linux/interrupt.h>
  20#include <linux/mc146818rtc.h>
  21#include <linux/bcd.h>
  22
  23#include <asm/sections.h>
  24#include <asm/prom.h>
  25#include <asm/io.h>
  26#include <asm/machdep.h>
  27#include <asm/time.h>
  28
  29#include "maple.h"
  30
  31#ifdef DEBUG
  32#define DBG(x...) printk(x)
  33#else
  34#define DBG(x...)
  35#endif
  36
  37static int maple_rtc_addr;
  38
  39static int maple_clock_read(int addr)
  40{
  41        outb_p(addr, maple_rtc_addr);
  42        return inb_p(maple_rtc_addr+1);
  43}
  44
  45static void maple_clock_write(unsigned long val, int addr)
  46{
  47        outb_p(addr, maple_rtc_addr);
  48        outb_p(val, maple_rtc_addr+1);
  49}
  50
  51void maple_get_rtc_time(struct rtc_time *tm)
  52{
  53        do {
  54                tm->tm_sec = maple_clock_read(RTC_SECONDS);
  55                tm->tm_min = maple_clock_read(RTC_MINUTES);
  56                tm->tm_hour = maple_clock_read(RTC_HOURS);
  57                tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
  58                tm->tm_mon = maple_clock_read(RTC_MONTH);
  59                tm->tm_year = maple_clock_read(RTC_YEAR);
  60        } while (tm->tm_sec != maple_clock_read(RTC_SECONDS));
  61
  62        if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
  63            || RTC_ALWAYS_BCD) {
  64                tm->tm_sec = bcd2bin(tm->tm_sec);
  65                tm->tm_min = bcd2bin(tm->tm_min);
  66                tm->tm_hour = bcd2bin(tm->tm_hour);
  67                tm->tm_mday = bcd2bin(tm->tm_mday);
  68                tm->tm_mon = bcd2bin(tm->tm_mon);
  69                tm->tm_year = bcd2bin(tm->tm_year);
  70          }
  71        if ((tm->tm_year + 1900) < 1970)
  72                tm->tm_year += 100;
  73
  74        tm->tm_wday = -1;
  75}
  76
  77int maple_set_rtc_time(struct rtc_time *tm)
  78{
  79        unsigned char save_control, save_freq_select;
  80        int sec, min, hour, mon, mday, year;
  81
  82        spin_lock(&rtc_lock);
  83
  84        save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  85
  86        maple_clock_write((save_control|RTC_SET), RTC_CONTROL);
  87
  88        save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  89
  90        maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  91
  92        sec = tm->tm_sec;
  93        min = tm->tm_min;
  94        hour = tm->tm_hour;
  95        mon = tm->tm_mon;
  96        mday = tm->tm_mday;
  97        year = tm->tm_year;
  98
  99        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 100                sec = bin2bcd(sec);
 101                min = bin2bcd(min);
 102                hour = bin2bcd(hour);
 103                mon = bin2bcd(mon);
 104                mday = bin2bcd(mday);
 105                year = bin2bcd(year);
 106        }
 107        maple_clock_write(sec, RTC_SECONDS);
 108        maple_clock_write(min, RTC_MINUTES);
 109        maple_clock_write(hour, RTC_HOURS);
 110        maple_clock_write(mon, RTC_MONTH);
 111        maple_clock_write(mday, RTC_DAY_OF_MONTH);
 112        maple_clock_write(year, RTC_YEAR);
 113
 114        /* The following flags have to be released exactly in this order,
 115         * otherwise the DS12887 (popular MC146818A clone with integrated
 116         * battery and quartz) will not reset the oscillator and will not
 117         * update precisely 500 ms later. You won't find this mentioned in
 118         * the Dallas Semiconductor data sheets, but who believes data
 119         * sheets anyway ...                           -- Markus Kuhn
 120         */
 121        maple_clock_write(save_control, RTC_CONTROL);
 122        maple_clock_write(save_freq_select, RTC_FREQ_SELECT);
 123
 124        spin_unlock(&rtc_lock);
 125
 126        return 0;
 127}
 128
 129static struct resource rtc_iores = {
 130        .name = "rtc",
 131        .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 132};
 133
 134time64_t __init maple_get_boot_time(void)
 135{
 136        struct rtc_time tm;
 137        struct device_node *rtcs;
 138
 139        rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
 140        if (rtcs) {
 141                struct resource r;
 142                if (of_address_to_resource(rtcs, 0, &r)) {
 143                        printk(KERN_EMERG "Maple: Unable to translate RTC"
 144                               " address\n");
 145                        goto bail;
 146                }
 147                if (!(r.flags & IORESOURCE_IO)) {
 148                        printk(KERN_EMERG "Maple: RTC address isn't PIO!\n");
 149                        goto bail;
 150                }
 151                maple_rtc_addr = r.start;
 152                printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n",
 153                       maple_rtc_addr);
 154        }
 155 bail:
 156        if (maple_rtc_addr == 0) {
 157                maple_rtc_addr = RTC_PORT(0); /* legacy address */
 158                printk(KERN_INFO "Maple: No device node for RTC, assuming "
 159                       "legacy address (0x%x)\n", maple_rtc_addr);
 160        }
 161
 162        rtc_iores.start = maple_rtc_addr;
 163        rtc_iores.end = maple_rtc_addr + 7;
 164        request_resource(&ioport_resource, &rtc_iores);
 165
 166        maple_get_rtc_time(&tm);
 167        return rtc_tm_to_time64(&tm);
 168}
 169
 170