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
  37 static int maple_rtc_addr;
  38
  39 static int maple_clock_read(int addr)
  40 {
  41         outb_p(addr, maple_rtc_addr);
  42         return inb_p(maple_rtc_addr+1);
  43 }
  44
  45 static 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
  51 void 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
  77 int 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
 129 static struct resource rtc_iores = {
 130         .name = "rtc",
 131         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 132 };
 133
 134 time64_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