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/system.h>
  31 #include <asm/io.h>
  32 #include <asm/pgtable.h>
  33 #include <asm/machdep.h>
  34 #include <asm/time.h>
  35
  36 #include "maple.h"
  37
  38 #ifdef DEBUG
  39 #define DBG(x...) printk(x)
  40 #else
  41 #define DBG(x...)
  42 #endif
  43
  44 static int maple_rtc_addr;
  45
  46 static int maple_clock_read(int addr)
  47 {
  48         outb_p(addr, maple_rtc_addr);
  49         return inb_p(maple_rtc_addr+1);
  50 }
  51
  52 static void maple_clock_write(unsigned long val, int addr)
  53 {
  54         outb_p(addr, maple_rtc_addr);
  55         outb_p(val, maple_rtc_addr+1);
  56 }
  57
  58 void maple_get_rtc_time(struct rtc_time *tm)
  59 {
  60         do {
  61                 tm->tm_sec = maple_clock_read(RTC_SECONDS);
  62                 tm->tm_min = maple_clock_read(RTC_MINUTES);
  63                 tm->tm_hour = maple_clock_read(RTC_HOURS);
  64                 tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
  65                 tm->tm_mon = maple_clock_read(RTC_MONTH);
  66                 tm->tm_year = maple_clock_read(RTC_YEAR);
  67         } while (tm->tm_sec != maple_clock_read(RTC_SECONDS));
  68
  69         if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
  70             || RTC_ALWAYS_BCD) {
  71                 tm->tm_sec = bcd2bin(tm->tm_sec);
  72                 tm->tm_min = bcd2bin(tm->tm_min);
  73                 tm->tm_hour = bcd2bin(tm->tm_hour);
  74                 tm->tm_mday = bcd2bin(tm->tm_mday);
  75                 tm->tm_mon = bcd2bin(tm->tm_mon);
  76                 tm->tm_year = bcd2bin(tm->tm_year);
  77           }
  78         if ((tm->tm_year + 1900) < 1970)
  79                 tm->tm_year += 100;
  80
  81         GregorianDay(tm);
  82 }
  83
  84 int maple_set_rtc_time(struct rtc_time *tm)
  85 {
  86         unsigned char save_control, save_freq_select;
  87         int sec, min, hour, mon, mday, year;
  88
  89         spin_lock(&rtc_lock);
  90
  91         save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */
  92
  93         maple_clock_write((save_control|RTC_SET), RTC_CONTROL);
  94
  95         save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */
  96
  97         maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
  98
  99         sec = tm->tm_sec;
 100         min = tm->tm_min;
 101         hour = tm->tm_hour;
 102         mon = tm->tm_mon;
 103         mday = tm->tm_mday;
 104         year = tm->tm_year;
 105
 106         if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
 107                 sec = bin2bcd(sec);
 108                 min = bin2bcd(min);
 109                 hour = bin2bcd(hour);
 110                 mon = bin2bcd(mon);
 111                 mday = bin2bcd(mday);
 112                 year = bin2bcd(year);
 113         }
 114         maple_clock_write(sec, RTC_SECONDS);
 115         maple_clock_write(min, RTC_MINUTES);
 116         maple_clock_write(hour, RTC_HOURS);
 117         maple_clock_write(mon, RTC_MONTH);
 118         maple_clock_write(mday, RTC_DAY_OF_MONTH);
 119         maple_clock_write(year, RTC_YEAR);
 120
 121         /* The following flags have to be released exactly in this order,
 122          * otherwise the DS12887 (popular MC146818A clone with integrated
 123          * battery and quartz) will not reset the oscillator and will not
 124          * update precisely 500 ms later. You won't find this mentioned in
 125          * the Dallas Semiconductor data sheets, but who believes data
 126          * sheets anyway ...                           -- Markus Kuhn
 127          */
 128         maple_clock_write(save_control, RTC_CONTROL);
 129         maple_clock_write(save_freq_select, RTC_FREQ_SELECT);
 130
 131         spin_unlock(&rtc_lock);
 132
 133         return 0;
 134 }
 135
 136 static struct resource rtc_iores = {
 137         .name = "rtc",
 138         .flags = IORESOURCE_BUSY,
 139 };
 140
 141 unsigned long __init maple_get_boot_time(void)
 142 {
 143         struct rtc_time tm;
 144         struct device_node *rtcs;
 145
 146         rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
 147         if (rtcs) {
 148                 struct resource r;
 149                 if (of_address_to_resource(rtcs, 0, &r)) {
 150                         printk(KERN_EMERG "Maple: Unable to translate RTC"
 151                                " address\n");
 152                         goto bail;
 153                 }
 154                 if (!(r.flags & IORESOURCE_IO)) {
 155                         printk(KERN_EMERG "Maple: RTC address isn't PIO!\n");
 156                         goto bail;
 157                 }
 158                 maple_rtc_addr = r.start;
 159                 printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n",
 160                        maple_rtc_addr);
 161         }
 162  bail:
 163         if (maple_rtc_addr == 0) {
 164                 maple_rtc_addr = RTC_PORT(0); /* legacy address */
 165                 printk(KERN_INFO "Maple: No device node for RTC, assuming "
 166                        "legacy address (0x%x)\n", maple_rtc_addr);
 167         }
 168
 169         rtc_iores.start = maple_rtc_addr;
 170         rtc_iores.end = maple_rtc_addr + 7;
 171         request_resource(&ioport_resource, &rtc_iores);
 172
 173         maple_get_rtc_time(&tm);
 174         return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
 175                       tm.tm_hour, tm.tm_min, tm.tm_sec);
 176 }
 177