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/*

 *  linux/include/asm-arm/arch-ebsa285/time.h

 *

 *  Copyright (C) 1998 Russell King.

 *  Copyright (C) 1998 Phil Blundell

 *

 * CATS has a real-time clock, though the evaluation board doesn't.

 *

 * Changelog:

 *  21-Mar-1998 RMK     Created

 *  27-Aug-1998 PJB     CATS support

 *  28-Dec-1998 APH     Made leds optional

 *  20-Jan-1999 RMK     Started merge of EBSA285, CATS and NetWinder

 *  16-Mar-1999 RMK     More support for EBSA285-like machines with RTCs in

 */

#define RTC_PORT(x)             (rtc_base+(x))

#define RTC_ALWAYS_BCD          0

#include <linux/mc146818rtc.h>

#include <asm/hardware/dec21285.h>

#include <asm/leds.h>

#include <asm/mach-types.h>

static int rtc_base;

#define mSEC_10_from_14 ((14318180 + 100) / 200)

static unsigned long isa_gettimeoffset(void)

{

        int count;

        static int count_p = (mSEC_10_from_14/6);    /* for the first call after boot */

        static unsigned long jiffies_p = 0;

        /*

         * cache volatile jiffies temporarily; we have IRQs turned off.

         */

        unsigned long jiffies_t;

        /* timer count may underflow right here */

        outb_p(0x00, 0x43);     /* latch the count ASAP */

        count = inb_p(0x40);    /* read the latched count */

        /*

         * We do this guaranteed double memory access instead of a _p

         * postfix in the previous port access. Wheee, hackady hack

         */

        jiffies_t = jiffies;

        count |= inb_p(0x40) << 8;

        /* Detect timer underflows.  If we haven't had a timer tick since

           the last time we were called, and time is apparently going

           backwards, the counter must have wrapped during this routine. */

        if ((jiffies_t == jiffies_p) && (count > count_p))

                count -= (mSEC_10_from_14/6);

        else

                jiffies_p = jiffies_t;

        count_p = count;

        count = (((mSEC_10_from_14/6)-1) - count) * tick;

        count = (count + (mSEC_10_from_14/6)/2) / (mSEC_10_from_14/6);

        return count;

}

static void isa_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)

{

        if (machine_is_netwinder())

                do_leds();

        do_timer(regs);

        do_set_rtc();

        do_profile(regs);

}

static unsigned long __init get_isa_cmos_time(void)

{

        unsigned int year, mon, day, hour, min, sec;

        int i;

        // check to see if the RTC makes sense.....

        if ((CMOS_READ(RTC_VALID) & RTC_VRT) == 0)

                return mktime(1970, 1, 1, 0, 0, 0);

        /* The Linux interpretation of the CMOS clock register contents:

         * When the Update-In-Progress (UIP) flag goes from 1 to 0, the

         * RTC registers show the second which has precisely just started.

         * Let's hope other operating systems interpret the RTC the same way.

         */

        /* read RTC exactly on falling edge of update flag */

        for (i = 0 ; i < 1000000 ; i++) /* may take up to 1 second... */

                if (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP)

                        break;

        for (i = 0 ; i < 1000000 ; i++) /* must try at least 2.228 ms */

                if (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))

                        break;

        do { /* Isn't this overkill ? UIP above should guarantee consistency */

                sec  = CMOS_READ(RTC_SECONDS);

                min  = CMOS_READ(RTC_MINUTES);

                hour = CMOS_READ(RTC_HOURS);

                day  = CMOS_READ(RTC_DAY_OF_MONTH);

                mon  = CMOS_READ(RTC_MONTH);

                year = CMOS_READ(RTC_YEAR);

        } while (sec != CMOS_READ(RTC_SECONDS));

        if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {

                BCD_TO_BIN(sec);

                BCD_TO_BIN(min);

                BCD_TO_BIN(hour);

                BCD_TO_BIN(day);

                BCD_TO_BIN(mon);

                BCD_TO_BIN(year);

        }

        if ((year += 1900) < 1970)

                year += 100;

        return mktime(year, mon, day, hour, min, sec);

}

static int

set_isa_cmos_time(void)

{

        int retval = 0;

        int real_seconds, real_minutes, cmos_minutes;

        unsigned char save_control, save_freq_select;

        unsigned long nowtime = xtime.tv_sec;

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

        CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);

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

        CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);

        cmos_minutes = CMOS_READ(RTC_MINUTES);

        if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)

                BCD_TO_BIN(cmos_minutes);

        /*

         * since we're only adjusting minutes and seconds,

         * don't interfere with hour overflow. This avoids

         * messing with unknown time zones but requires your

         * RTC not to be off by more than 15 minutes

         */

        real_seconds = nowtime % 60;

        real_minutes = nowtime / 60;

        if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1)

                real_minutes += 30;             /* correct for half hour time zone */

        real_minutes %= 60;

        if (abs(real_minutes - cmos_minutes) < 30) {

                if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {

                        BIN_TO_BCD(real_seconds);

                        BIN_TO_BCD(real_minutes);

                }

                CMOS_WRITE(real_seconds,RTC_SECONDS);

                CMOS_WRITE(real_minutes,RTC_MINUTES);

        } else

                retval = -1;

        /* 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

         */

        CMOS_WRITE(save_control, RTC_CONTROL);

        CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);

        return retval;

}

static unsigned long timer1_gettimeoffset (void)

{

        unsigned long value = LATCH - *CSR_TIMER1_VALUE;

        return (tick * value) / LATCH;

}

static void timer1_interrupt(int irq, void *dev_id, struct pt_regs *regs)

{

        *CSR_TIMER1_CLR = 0;

        /* Do the LEDs things */

        do_leds();

        do_timer(regs);

        do_set_rtc();

        do_profile(regs);

}

/*

 * Set up timer interrupt.

 */

static inline void setup_timer(void)

{

        int irq;

        if (machine_is_co285() ||

            machine_is_personal_server())

                /*

                 * Add-in 21285s shouldn't access the RTC

                 */

                rtc_base = 0;

        else

                rtc_base = 0x70;

        if (rtc_base) {

                int reg_d, reg_b;

                /*

                 * Probe for the RTC.

                 */

                reg_d = CMOS_READ(RTC_REG_D);

                /*

                 * make sure the divider is set

                 */

                CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);

                /*

                 * Set control reg B

                 *   (24 hour mode, update enabled)

                 */

                reg_b = CMOS_READ(RTC_REG_B) & 0x7f;

                reg_b |= 2;

                CMOS_WRITE(reg_b, RTC_REG_B);

                if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&

                    CMOS_READ(RTC_REG_B) == reg_b) {

                        /*

                         * We have a RTC.  Check the battery

                         */

                        if ((reg_d & 0x80) == 0)

                                printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");

                        xtime.tv_sec = get_isa_cmos_time();

                        set_rtc = set_isa_cmos_time;

                } else

                        rtc_base = 0;

        }

        if (machine_is_ebsa285() ||

            machine_is_co285() ||

            machine_is_personal_server()) {

                gettimeoffset = timer1_gettimeoffset;

                *CSR_TIMER1_CLR  = 0;

                *CSR_TIMER1_LOAD = LATCH;

                *CSR_TIMER1_CNTL = TIMER_CNTL_ENABLE | TIMER_CNTL_AUTORELOAD | TIMER_CNTL_DIV16;

                timer_irq.handler = timer1_interrupt;

                irq = IRQ_TIMER1;

        } else {

                /* enable PIT timer */

                /* set for periodic (4) and LSB/MSB write (0x30) */

                outb(0x34, 0x43);

                outb((mSEC_10_from_14/6) & 0xFF, 0x40);

                outb((mSEC_10_from_14/6) >> 8, 0x40);

                gettimeoffset = isa_gettimeoffset;

                timer_irq.handler = isa_timer_interrupt;

                irq = IRQ_ISA_TIMER;

        }

        setup_arm_irq(irq, &timer_irq);

}