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/errno.h>
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/param.h>
  18 #include <linux/string.h>
  19 #include <linux/mm.h>
  20 #include <linux/init.h>
  21 #include <linux/time.h>
  22 #include <linux/adb.h>
  23 #include <linux/pmu.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/mc146818rtc.h>
  26 #include <linux/bcd.h>
  27
  28 #include <asm/sections.h>
  29 #include <asm/prom.h>
  30 #include <asm/io.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/machdep.h>
  33 #include <asm/time.h>
  34
  35 #include "maple.h"
  36
  37 #ifdef DEBUG
  38 #define DBG(x...) printk(x)
  39 #else
  40 #define DBG(x...)
  41 #endif
  42
  43 static int maple_rtc_addr;
  44
  45 static int maple_clock_read(int addr)
  46 {
  47         outb_p(addr, maple_rtc_addr);
  48         return inb_p(maple_rtc_addr+1);
  49 }
  50
  51 static void maple_clock_write(unsigned long val, int addr)
  52 {
  53         outb_p(addr, maple_rtc_addr);
  54         outb_p(val, maple_rtc_addr+1);
  55 }
  56
  57 void maple_get_rtc_time(struct rtc_time *tm)
  58 {
  59         do {
  60                 tm->tm_sec = maple_clock_read(RTC_SECONDS);
  61                 tm->tm_min = maple_clock_read(RTC_MINUTES);
  62                 tm->tm_hour = maple_clock_read(RTC_HOURS);
  63                 tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
  64                 tm->tm_mon = maple_clock_read(RTC_MONTH);
  65                 tm->tm_year = maple_clock_read(RTC_YEAR);
  66         } while (tm->tm_sec != maple_clock_read(RTC_SECONDS));
  67
  68         if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
  69             || RTC_ALWAYS_BCD) {
  70                 tm->tm_sec = bcd2bin(tm->tm_sec);
  71                 tm->tm_min = bcd2bin(tm->tm_min);
  72                 tm->tm_hour = bcd2bin(tm->tm_hour);
  73                 tm->tm_mday = bcd2bin(tm->tm_mday);
  74                 tm->tm_mon = bcd2bin(tm->tm_mon);
  75                 tm->tm_year = bcd2bin(tm->tm_year);
  76           }
  77         if ((tm->tm_year + 1900) < 1970)
  78                 tm->tm_year += 100;
  79
  80         tm->tm_wday = -1;
  81 }
  82
  83 int maple_set_rtc_time(struct rtc_time *tm)
  84 {
  85         unsigned char save_control, save_freq_select;
  86         int sec, min, hour, mon, mday, year;
  87
  88         spin_lock(&rtc_lock);
  89
  90         save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  91
  92         maple_clock_write((save_control|RTC_SET), RTC_CONTROL);
  93
  94         save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  95
  96         maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  97
  98         sec = tm->tm_sec;
  99         min = tm->tm_min;
 100         hour = tm->tm_hour;
 101         mon = tm->tm_mon;
 102         mday = tm->tm_mday;
 103         year = tm->tm_year;
 104
 105         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 106                 sec = bin2bcd(sec);
 107                 min = bin2bcd(min);
 108                 hour = bin2bcd(hour);
 109                 mon = bin2bcd(mon);
 110                 mday = bin2bcd(mday);
 111                 year = bin2bcd(year);
 112         }
 113         maple_clock_write(sec, RTC_SECONDS);
 114         maple_clock_write(min, RTC_MINUTES);
 115         maple_clock_write(hour, RTC_HOURS);
 116         maple_clock_write(mon, RTC_MONTH);
 117         maple_clock_write(mday, RTC_DAY_OF_MONTH);
 118         maple_clock_write(year, RTC_YEAR);
 119
 120         /* The following flags have to be released exactly in this order,
 121          * otherwise the DS12887 (popular MC146818A clone with integrated
 122          * battery and quartz) will not reset the oscillator and will not
 123          * update precisely 500 ms later. You won't find this mentioned in
 124          * the Dallas Semiconductor data sheets, but who believes data
 125          * sheets anyway ...                           -- Markus Kuhn
 126          */
 127         maple_clock_write(save_control, RTC_CONTROL);
 128         maple_clock_write(save_freq_select, RTC_FREQ_SELECT);
 129
 130         spin_unlock(&rtc_lock);
 131
 132         return 0;
 133 }
 134
 135 static struct resource rtc_iores = {
 136         .name = "rtc",
 137         .flags = IORESOURCE_IO | IORESOURCE_BUSY,
 138 };
 139
 140 unsigned long __init maple_get_boot_time(void)
 141 {
 142         struct rtc_time tm;
 143         struct device_node *rtcs;
 144
 145         rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
 146         if (rtcs) {
 147                 struct resource r;
 148                 if (of_address_to_resource(rtcs, 0, &r)) {
 149                         printk(KERN_EMERG "Maple: Unable to translate RTC"
 150                                " address\n");
 151                         goto bail;
 152                 }
 153                 if (!(r.flags & IORESOURCE_IO)) {
 154                         printk(KERN_EMERG "Maple: RTC address isn't PIO!\n");
 155                         goto bail;
 156                 }
 157                 maple_rtc_addr = r.start;
 158                 printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n",
 159                        maple_rtc_addr);
 160         }
 161  bail:
 162         if (maple_rtc_addr == 0) {
 163                 maple_rtc_addr = RTC_PORT(0); /* legacy address */
 164                 printk(KERN_INFO "Maple: No device node for RTC, assuming "
 165                        "legacy address (0x%x)\n", maple_rtc_addr);
 166         }
 167
 168         rtc_iores.start = maple_rtc_addr;
 169         rtc_iores.end = maple_rtc_addr + 7;
 170         request_resource(&ioport_resource, &rtc_iores);
 171
 172         maple_get_rtc_time(&tm);
 173         return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
 174                       tm.tm_hour, tm.tm_min, tm.tm_sec);
 175 }
 176