/* 
 * include/asm-generic/rtc.h
 *
 * Author: Tom Rini <trini@mvista.com>
 *
 * Based on:
 * drivers/char/rtc.c
 *
 * Please read the COPYING file for all license details.
 */

#ifndef __ASM_RTC_H__
#define __ASM_RTC_H__

#ifdef __KERNEL__

#include <linux/mc146818rtc.h>
#include <linux/rtc.h>
#include <linux/bcd.h>

#define RTC_PIE 0x40            /* periodic interrupt enable */
#define RTC_AIE 0x20            /* alarm interrupt enable */
#define RTC_UIE 0x10            /* update-finished interrupt enable */

/* some dummy definitions */
#define RTC_BATT_BAD 0x100      /* battery bad */
#define RTC_SQWE 0x08           /* enable square-wave output */
#define RTC_DM_BINARY 0x04      /* all time/date values are BCD if clear */
#define RTC_24H 0x02            /* 24 hour mode - else hours bit 7 means pm */
#define RTC_DST_EN 0x01         /* auto switch DST - works f. USA only */

/*
 * Returns true if a clock update is in progress
 */
static inline unsigned char rtc_is_updating(void)
{
        unsigned char uip;

        spin_lock_irq(&rtc_lock);
        uip = (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
        spin_unlock_irq(&rtc_lock);
        return uip;
}

static inline unsigned int get_rtc_time(struct rtc_time *time)
{
        unsigned long uip_watchdog = jiffies;
        unsigned char ctrl;
#ifdef CONFIG_MACH_DECSTATION
        unsigned int real_year;
#endif

        /*
         * read RTC once any update in progress is done. The update
         * can take just over 2ms. We wait 10 to 20ms. There is no need to
         * to poll-wait (up to 1s - eeccch) for the falling edge of RTC_UIP.
         * If you need to know *exactly* when a second has started, enable
         * periodic update complete interrupts, (via ioctl) and then 
         * immediately read /dev/rtc which will block until you get the IRQ.
         * Once the read clears, read the RTC time (again via ioctl). Easy.
         */

        if (rtc_is_updating() != 0)
                while (jiffies - uip_watchdog < 2*HZ/100) {
                        barrier();
                        cpu_relax();
                }

        /*
         * Only the values that we read from the RTC are set. We leave
         * tm_wday, tm_yday and tm_isdst untouched. Even though the
         * RTC has RTC_DAY_OF_WEEK, we ignore it, as it is only updated
         * by the RTC when initially set to a non-zero value.
         */
        spin_lock_irq(&rtc_lock);
        time->tm_sec = CMOS_READ(RTC_SECONDS);
        time->tm_min = CMOS_READ(RTC_MINUTES);
        time->tm_hour = CMOS_READ(RTC_HOURS);
        time->tm_mday = CMOS_READ(RTC_DAY_OF_MONTH);
        time->tm_mon = CMOS_READ(RTC_MONTH);
        time->tm_year = CMOS_READ(RTC_YEAR);
#ifdef CONFIG_MACH_DECSTATION
        real_year = CMOS_READ(RTC_DEC_YEAR);
#endif
        ctrl = CMOS_READ(RTC_CONTROL);
        spin_unlock_irq(&rtc_lock);

        if (!(ctrl & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
        {
                BCD_TO_BIN(time->tm_sec);
                BCD_TO_BIN(time->tm_min);
                BCD_TO_BIN(time->tm_hour);
                BCD_TO_BIN(time->tm_mday);
                BCD_TO_BIN(time->tm_mon);
                BCD_TO_BIN(time->tm_year);
        }

#ifdef CONFIG_MACH_DECSTATION
        time->tm_year += real_year - 72;
#endif

        /*
         * Account for differences between how the RTC uses the values
         * and how they are defined in a struct rtc_time;
         */
        if (time->tm_year <= 69)
                time->tm_year += 100;

        time->tm_mon--;

        return RTC_24H;
}

/* Set the current date and time in the real time clock. */
static inline int set_rtc_time(struct rtc_time *time)
{
        unsigned long flags;
        unsigned char mon, day, hrs, min, sec;
        unsigned char save_control, save_freq_select;
        unsigned int yrs;
#ifdef CONFIG_MACH_DECSTATION
        unsigned int real_yrs, leap_yr;
#endif

        yrs = time->tm_year;
        mon = time->tm_mon + 1;   /* tm_mon starts at zero */
        day = time->tm_mday;
        hrs = time->tm_hour;
        min = time->tm_min;
        sec = time->tm_sec;

        if (yrs > 255)  /* They are unsigned */
                return -EINVAL;

        spin_lock_irqsave(&rtc_lock, flags);
#ifdef CONFIG_MACH_DECSTATION
        real_yrs = yrs;
        leap_yr = ((!((yrs + 1900) % 4) && ((yrs + 1900) % 100)) ||
                        !((yrs + 1900) % 400));
        yrs = 72;

        /*
         * We want to keep the year set to 73 until March
         * for non-leap years, so that Feb, 29th is handled
         * correctly.
         */
        if (!leap_yr && mon < 3) {
                real_yrs--;
                yrs = 73;
        }
#endif
        /* These limits and adjustments are independent of
         * whether the chip is in binary mode or not.
         */
        if (yrs > 169) {
                spin_unlock_irqrestore(&rtc_lock, flags);
                return -EINVAL;
        }

        if (yrs >= 100)
                yrs -= 100;

        if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY)
            || RTC_ALWAYS_BCD) {
                BIN_TO_BCD(sec);
                BIN_TO_BCD(min);
                BIN_TO_BCD(hrs);
                BIN_TO_BCD(day);
                BIN_TO_BCD(mon);
                BIN_TO_BCD(yrs);
        }

        save_control = CMOS_READ(RTC_CONTROL);
        CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
        save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
        CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

#ifdef CONFIG_MACH_DECSTATION
        CMOS_WRITE(real_yrs, RTC_DEC_YEAR);
#endif
        CMOS_WRITE(yrs, RTC_YEAR);
        CMOS_WRITE(mon, RTC_MONTH);
        CMOS_WRITE(day, RTC_DAY_OF_MONTH);
        CMOS_WRITE(hrs, RTC_HOURS);
        CMOS_WRITE(min, RTC_MINUTES);
        CMOS_WRITE(sec, RTC_SECONDS);

        CMOS_WRITE(save_control, RTC_CONTROL);
        CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);

        spin_unlock_irqrestore(&rtc_lock, flags);

        return 0;
}

static inline unsigned int get_rtc_ss(void)
{
        struct rtc_time h;

        get_rtc_time(&h);
        return h.tm_sec;
}

static inline int get_rtc_pll(struct rtc_pll_info *pll)
{
        return -EINVAL;
}
static inline int set_rtc_pll(struct rtc_pll_info *pll)
{
        return -EINVAL;
}

#endif /* __KERNEL__ */
#endif /* __ASM_RTC_H__ */