/*
 *  (c) Copyright 2004 Benjamin Herrenschmidt (benh@kernel.crashing.org),
 *                     IBM Corp. 
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 *
 */

#undef DEBUG

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/time.h>
#include <linux/adb.h>
#include <linux/pmu.h>
#include <linux/interrupt.h>
#include <linux/mc146818rtc.h>
#include <linux/bcd.h>

#include <asm/sections.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/machdep.h>
#include <asm/time.h>

#include "maple.h"

#ifdef DEBUG
#define DBG(x...) printk(x)
#else
#define DBG(x...)
#endif

static int maple_rtc_addr;

static int maple_clock_read(int addr)
{
        outb_p(addr, maple_rtc_addr);
        return inb_p(maple_rtc_addr+1);
}

static void maple_clock_write(unsigned long val, int addr)
{
        outb_p(addr, maple_rtc_addr);
        outb_p(val, maple_rtc_addr+1);
}

void maple_get_rtc_time(struct rtc_time *tm)
{
        do {
                tm->tm_sec = maple_clock_read(RTC_SECONDS);
                tm->tm_min = maple_clock_read(RTC_MINUTES);
                tm->tm_hour = maple_clock_read(RTC_HOURS);
                tm->tm_mday = maple_clock_read(RTC_DAY_OF_MONTH);
                tm->tm_mon = maple_clock_read(RTC_MONTH);
                tm->tm_year = maple_clock_read(RTC_YEAR);
        } while (tm->tm_sec != maple_clock_read(RTC_SECONDS));

        if (!(maple_clock_read(RTC_CONTROL) & RTC_DM_BINARY)
            || RTC_ALWAYS_BCD) {
                tm->tm_sec = bcd2bin(tm->tm_sec);
                tm->tm_min = bcd2bin(tm->tm_min);
                tm->tm_hour = bcd2bin(tm->tm_hour);
                tm->tm_mday = bcd2bin(tm->tm_mday);
                tm->tm_mon = bcd2bin(tm->tm_mon);
                tm->tm_year = bcd2bin(tm->tm_year);
          }
        if ((tm->tm_year + 1900) < 1970)
                tm->tm_year += 100;

        GregorianDay(tm);
}

int maple_set_rtc_time(struct rtc_time *tm)
{
        unsigned char save_control, save_freq_select;
        int sec, min, hour, mon, mday, year;

        spin_lock(&rtc_lock);

        save_control = maple_clock_read(RTC_CONTROL); /* tell the clock it's being set */

        maple_clock_write((save_control|RTC_SET), RTC_CONTROL);

        save_freq_select = maple_clock_read(RTC_FREQ_SELECT); /* stop and reset prescaler */

        maple_clock_write((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

        sec = tm->tm_sec;
        min = tm->tm_min;
        hour = tm->tm_hour;
        mon = tm->tm_mon;
        mday = tm->tm_mday;
        year = tm->tm_year;

        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
                sec = bin2bcd(sec);
                min = bin2bcd(min);
                hour = bin2bcd(hour);
                mon = bin2bcd(mon);
                mday = bin2bcd(mday);
                year = bin2bcd(year);
        }
        maple_clock_write(sec, RTC_SECONDS);
        maple_clock_write(min, RTC_MINUTES);
        maple_clock_write(hour, RTC_HOURS);
        maple_clock_write(mon, RTC_MONTH);
        maple_clock_write(mday, RTC_DAY_OF_MONTH);
        maple_clock_write(year, RTC_YEAR);

        /* The following flags have to be released exactly in this order,
         * otherwise the DS12887 (popular MC146818A clone with integrated
         * battery and quartz) will not reset the oscillator and will not
         * update precisely 500 ms later. You won't find this mentioned in
         * the Dallas Semiconductor data sheets, but who believes data
         * sheets anyway ...                           -- Markus Kuhn
         */
        maple_clock_write(save_control, RTC_CONTROL);
        maple_clock_write(save_freq_select, RTC_FREQ_SELECT);

        spin_unlock(&rtc_lock);

        return 0;
}

static struct resource rtc_iores = {
        .name = "rtc",
        .flags = IORESOURCE_BUSY,
};

unsigned long __init maple_get_boot_time(void)
{
        struct rtc_time tm;
        struct device_node *rtcs;

        rtcs = of_find_compatible_node(NULL, "rtc", "pnpPNP,b00");
        if (rtcs) {
                struct resource r;
                if (of_address_to_resource(rtcs, 0, &r)) {
                        printk(KERN_EMERG "Maple: Unable to translate RTC"
                               " address\n");
                        goto bail;
                }
                if (!(r.flags & IORESOURCE_IO)) {
                        printk(KERN_EMERG "Maple: RTC address isn't PIO!\n");
                        goto bail;
                }
                maple_rtc_addr = r.start;
                printk(KERN_INFO "Maple: Found RTC at IO 0x%x\n",
                       maple_rtc_addr);
        }
 bail:
        if (maple_rtc_addr == 0) {
                maple_rtc_addr = RTC_PORT(0); /* legacy address */
                printk(KERN_INFO "Maple: No device node for RTC, assuming "
                       "legacy address (0x%x)\n", maple_rtc_addr);
        }

        rtc_iores.start = maple_rtc_addr;
        rtc_iores.end = maple_rtc_addr + 7;
        request_resource(&ioport_resource, &rtc_iores);

        maple_get_rtc_time(&tm);
        return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
                      tm.tm_hour, tm.tm_min, tm.tm_sec);
}