arch/powerpc/platforms/maple/time.c

   1 /*
   2  *  (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org),
   3  *                     IBM Corp.
   4  *
   5  *  This program is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU General Public License
   7  *  as published by the Free Software Foundation; either version
   8  *  2 of the License, or (at your option) any later version.
   9  *
  10  */
  11
  12 #undef DEBUG
  13
  14 #include <linux/config.h>
  15 #include <linux/errno.h>
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/param.h>
  19 #include <linux/string.h>
  20 #include <linux/mm.h>
  21 #include <linux/init.h>
  22 #include <linux/time.h>
  23 #include <linux/adb.h>
  24 #include <linux/pmu.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/mc146818rtc.h>
  27 #include <linux/bcd.h>
  28
  29 #include <asm/sections.h>
  30 #include <asm/prom.h>
  31 #include <asm/system.h>
  32 #include <asm/io.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/machdep.h>
  35 #include <asm/time.h>
  36
  37 #include "maple.h"
  38
  39 #ifdef DEBUG
  40 #define DBG(x...) printk(x)
  41 #else
  42 #define DBG(x...)
  43 #endif
  44
  45 extern void GregorianDay(struct rtc_time * tm);
  46
  47 static int maple_rtc_addr;
  48
  49 static int maple_clock_read(int addr)
  50 {
  51         outb_p(addr, maple_rtc_addr);
  52         return inb_p(maple_rtc_addr+1);
  53 }
  54
  55 static void maple_clock_write(unsigned long val, int addr)
  56 {
  57         outb_p(addr, maple_rtc_addr);
  58         outb_p(val, maple_rtc_addr+1);
  59 }
  60
  61 void maple_get_rtc_time(struct rtc_time *tm)
  62 {
  63         do {
  64                 tm->tm_sec = maple_clock_read(RTC_SECONDS);
  65                 tm->tm_min = maple_clock_read(RTC_MINUTES);
  66                 tm->tm_hour = maple_clock_read(RTC_HOURS);
  67                 tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
  68                 tm->tm_mon = maple_clock_read(RTC_MONTH);
  69                 tm->tm_year = maple_clock_read(RTC_YEAR);
  70         } while (tm->tm_sec != maple_clock_read(RTC_SECONDS));
  71
  72         if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
  73             || RTC_ALWAYS_BCD) {
  74                 BCD_TO_BIN(tm->tm_sec);
  75                 BCD_TO_BIN(tm->tm_min);
  76                 BCD_TO_BIN(tm->tm_hour);
  77                 BCD_TO_BIN(tm->tm_mday);
  78                 BCD_TO_BIN(tm->tm_mon);
  79                 BCD_TO_BIN(tm->tm_year);
  80           }
  81         if ((tm->tm_year + 1900) < 1970)
  82                 tm->tm_year += 100;
  83
  84         GregorianDay(tm);
  85 }
  86
  87 int maple_set_rtc_time(struct rtc_time *tm)
  88 {
  89         unsigned char save_control, save_freq_select;
  90         int sec, min, hour, mon, mday, year;
  91
  92         spin_lock(&rtc_lock);
  93
  94         save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  95
  96         maple_clock_write((save_control|RTC_SET), RTC_CONTROL);
  97
  98         save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  99
 100         maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
 101
 102         sec = tm->tm_sec;
 103         min = tm->tm_min;
 104         hour = tm->tm_hour;
 105         mon = tm->tm_mon;
 106         mday = tm->tm_mday;
 107         year = tm->tm_year;
 108
 109         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 110                 BIN_TO_BCD(sec);
 111                 BIN_TO_BCD(min);
 112                 BIN_TO_BCD(hour);
 113                 BIN_TO_BCD(mon);
 114                 BIN_TO_BCD(mday);
 115                 BIN_TO_BCD(year);
 116         }
 117         maple_clock_write(sec, RTC_SECONDS);
 118         maple_clock_write(min, RTC_MINUTES);
 119         maple_clock_write(hour, RTC_HOURS);
 120         maple_clock_write(mon, RTC_MONTH);
 121         maple_clock_write(mday, RTC_DAY_OF_MONTH);
 122         maple_clock_write(year, RTC_YEAR);
 123
 124         /* The following flags have to be released exactly in this order,
 125          * otherwise the DS12887 (popular MC146818A clone with integrated
 126          * battery and quartz) will not reset the oscillator and will not
 127          * update precisely 500 ms later. You won't find this mentioned in
 128          * the Dallas Semiconductor data sheets, but who believes data
 129          * sheets anyway ...                           -- Markus Kuhn
 130          */
 131         maple_clock_write(save_control, RTC_CONTROL);
 132         maple_clock_write(save_freq_select, RTC_FREQ_SELECT);
 133
 134         spin_unlock(&rtc_lock);
 135
 136         return 0;
 137 }
 138
 139 static struct resource rtc_iores = {
 140         .name = "rtc",
 141         .flags = IORESOURCE_BUSY,
 142 };
 143
 144 unsigned long __init maple_get_boot_time(void)
 145 {
 146         struct rtc_time tm;
 147         struct device_node *rtcs;
 148
 149         rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
 150         if (rtcs) {
 151                 struct resource r;
 152                 if (of_address_to_resource(rtcs, 0, &r)) {
 153                         printk(KERN_EMERG "Maple: Unable to translate RTC"
 154                                " address\n");
 155                         goto bail;
 156                 }
 157                 if (!(r.flags & IORESOURCE_IO)) {
 158                         printk(KERN_EMERG "Maple: RTC address isn't PIO!\n");
 159                         goto bail;
 160                 }
 161                 maple_rtc_addr = r.start;
 162                 printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n",
 163                        maple_rtc_addr);
 164         }
 165  bail:
 166         if (maple_rtc_addr == 0) {
 167                 maple_rtc_addr = RTC_PORT(0); /* legacy address */
 168                 printk(KERN_INFO "Maple: No device node for RTC, assuming "
 169                        "legacy address (0x%x)\n", maple_rtc_addr);
 170         }
 171
 172         rtc_iores.start = maple_rtc_addr;
 173         rtc_iores.end = maple_rtc_addr + 7;
 174         request_resource(&ioport_resource, &rtc_iores);
 175
 176         maple_get_rtc_time(&tm);
 177         return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
 178                       tm.tm_hour, tm.tm_min, tm.tm_sec);
 179 }
 180