2.2.0-final

[davej-history.git] / arch / sparc64 / kernel / time.c

/* $Id: time.c,v 1.16 1998/09/05 17:25:28 jj Exp $
 * time.c: UltraSparc timer and TOD clock support.
 *
 * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1998 Eddie C. Dost   (ecd@skynet.be)
 *
 * Based largely on code which is:
 *
 * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
 */

#include <linux/config.h>
#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/interrupt.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/ioport.h>

#include <asm/oplib.h>
#include <asm/mostek.h>
#include <asm/timer.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/sbus.h>
#include <asm/fhc.h>
#include <asm/pbm.h>
#include <asm/ebus.h>

struct mostek48t02 *mstk48t02_regs = 0;
static struct mostek48t08 *mstk48t08_regs = 0;
static struct mostek48t59 *mstk48t59_regs = 0;

static int set_rtc_mmss(unsigned long);

/* timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 *
 * NOTE: On SUN5 systems the ticker interrupt comes in using 2
 *       interrupts, one at level14 and one with softint bit 0.
 */
unsigned long timer_tick_offset;
static unsigned long timer_tick_compare;
static unsigned long timer_ticks_per_usec;

static __inline__ void timer_check_rtc(void)
{
        /* last time the cmos clock got updated */
        static long last_rtc_update=0;

        /* Determine when to update the Mostek clock. */
        if ((time_status & STA_UNSYNC) == 0 &&
            xtime.tv_sec > last_rtc_update + 660 &&
            xtime.tv_usec >= 500000 - ((unsigned) tick) / 2 &&
            xtime.tv_usec <= 500000 + ((unsigned) tick) / 2) {
                if (set_rtc_mmss(xtime.tv_sec) == 0)
                        last_rtc_update = xtime.tv_sec;
                else
                        last_rtc_update = xtime.tv_sec - 600;
                        /* do it again in 60 s */
        }
}

static void timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        unsigned long ticks;

        do {
                do_timer(regs);

                __asm__ __volatile__("
                        rd      %%tick_cmpr, %0
                        add     %0, %2, %0
                        wr      %0, 0, %%tick_cmpr
                        rd      %%tick, %1"
                        : "=&r" (timer_tick_compare), "=r" (ticks)
                        : "r" (timer_tick_offset));
        } while (ticks >= timer_tick_compare);

        timer_check_rtc();
}

#ifdef __SMP__
void timer_tick_interrupt(struct pt_regs *regs)
{
        do_timer(regs);

        /*
         * Only keep timer_tick_offset uptodate, but don't set TICK_CMPR.
         */
        __asm__ __volatile__("
                rd      %%tick_cmpr, %0
                add     %0, %1, %0"
                : "=&r" (timer_tick_compare)
                : "r" (timer_tick_offset));

        timer_check_rtc();
}
#endif

/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
 * Assumes input in normal date format, i.e. 1980-12-31 23:59:59
 * => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
 *
 * [For the Julian calendar (which was used in Russia before 1917,
 * Britain & colonies before 1752, anywhere else before 1582,
 * and is still in use by some communities) leave out the
 * -year/100+year/400 terms, and add 10.]
 *
 * This algorithm was first published by Gauss (I think).
 *
 * WARNING: this function will overflow on 2106-02-07 06:28:16 on
 * machines were long is 32-bit! (However, as time_t is signed, we
 * will already get problems at other places on 2038-01-19 03:14:08)
 */
static inline unsigned long mktime(unsigned int year, unsigned int mon,
        unsigned int day, unsigned int hour,
        unsigned int min, unsigned int sec)
{
        if (0 >= (int) (mon -= 2)) {    /* 1..12 -> 11,12,1..10 */
                mon += 12;      /* Puts Feb last since it has leap day */
                year -= 1;
        }
        return (((
            (unsigned long)(year/4 - year/100 + year/400 + 367*mon/12 + day) +
              year*365 - 719499
            )*24 + hour /* now have hours */
           )*60 + min /* now have minutes */
          )*60 + sec; /* finally seconds */
}

/* Kick start a stopped clock (procedure from the Sun NVRAM/hostid FAQ). */
static void __init kick_start_clock(void)
{
        register struct mostek48t02 *regs = mstk48t02_regs;
        unsigned char sec;
        int i, count;

        prom_printf("CLOCK: Clock was stopped. Kick start ");

        /* Turn on the kick start bit to start the oscillator. */
        regs->creg |= MSTK_CREG_WRITE;
        regs->sec &= ~MSTK_STOP;
        regs->hour |= MSTK_KICK_START;
        regs->creg &= ~MSTK_CREG_WRITE;

        /* Delay to allow the clock oscillator to start. */
        sec = MSTK_REG_SEC(regs);
        for (i = 0; i < 3; i++) {
                while (sec == MSTK_REG_SEC(regs))
                        for (count = 0; count < 100000; count++)
                                /* nothing */ ;
                prom_printf(".");
                sec = regs->sec;
        }
        prom_printf("\n");

        /* Turn off kick start and set a "valid" time and date. */
        regs->creg |= MSTK_CREG_WRITE;
        regs->hour &= ~MSTK_KICK_START;
        MSTK_SET_REG_SEC(regs,0);
        MSTK_SET_REG_MIN(regs,0);
        MSTK_SET_REG_HOUR(regs,0);
        MSTK_SET_REG_DOW(regs,5);
        MSTK_SET_REG_DOM(regs,1);
        MSTK_SET_REG_MONTH(regs,8);
        MSTK_SET_REG_YEAR(regs,1996 - MSTK_YEAR_ZERO);
        regs->creg &= ~MSTK_CREG_WRITE;

        /* Ensure the kick start bit is off. If it isn't, turn it off. */
        while (regs->hour & MSTK_KICK_START) {
                prom_printf("CLOCK: Kick start still on!\n");
                regs->creg |= MSTK_CREG_WRITE;
                regs->hour &= ~MSTK_KICK_START;
                regs->creg &= ~MSTK_CREG_WRITE;
        }

        prom_printf("CLOCK: Kick start procedure successful.\n");
}

/* Return nonzero if the clock chip battery is low. */
static int __init has_low_battery(void)
{
        register struct mostek48t02 *regs = mstk48t02_regs;
        unsigned char data1, data2;

        data1 = regs->eeprom[0];        /* Read some data. */
        regs->eeprom[0] = ~data1;       /* Write back the complement. */
        data2 = regs->eeprom[0];        /* Read back the complement. */
        regs->eeprom[0] = data1;        /* Restore the original value. */

        return (data1 == data2);        /* Was the write blocked? */
}


/* Probe for the real time clock chip. */
static void __init set_system_time(void)
{
        unsigned int year, mon, day, hour, min, sec;
        struct mostek48t02 *mregs;

        do_get_fast_time = do_gettimeofday;

        mregs = mstk48t02_regs;
        if(!mregs) {
                prom_printf("Something wrong, clock regs not mapped yet.\n");
                prom_halt();
        }               

        mregs->creg |= MSTK_CREG_READ;
        sec = MSTK_REG_SEC(mregs);
        min = MSTK_REG_MIN(mregs);
        hour = MSTK_REG_HOUR(mregs);
        day = MSTK_REG_DOM(mregs);
        mon = MSTK_REG_MONTH(mregs);
        year = MSTK_CVT_YEAR( MSTK_REG_YEAR(mregs) );
        xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
        xtime.tv_usec = 0;
        mregs->creg &= ~MSTK_CREG_READ;
}

void __init clock_probe(void)
{
        struct linux_prom_registers clk_reg[2];
        char model[128];
        int node, busnd = -1, err;
        unsigned long flags;
#ifdef CONFIG_PCI
        struct linux_ebus *ebus = 0;
#endif

        __save_and_cli(flags);

        if(central_bus != NULL) {
                busnd = central_bus->child->prom_node;
        }
#ifdef CONFIG_PCI
        else if (ebus_chain != NULL) {
                ebus = ebus_chain;
                busnd = ebus->prom_node;
        }
#endif
        else {
                busnd = SBus_chain->prom_node;
        }

        if(busnd == -1) {
                prom_printf("clock_probe: problem, cannot find bus to search.\n");
                prom_halt();
        }

        node = prom_getchild(busnd);

        while(1) {
                prom_getstring(node, "model", model, sizeof(model));
                if(strcmp(model, "mk48t02") &&
                   strcmp(model, "mk48t08") &&
                   strcmp(model, "mk48t59")) {
                        node = prom_getsibling(node);
#ifdef CONFIG_PCI
                        if ((node == 0) && ebus) {
                                ebus = ebus->next;
                                if (ebus) {
                                        busnd = ebus->prom_node;
                                        node = prom_getchild(busnd);
                                }
                        }
#endif
                        if(node == 0) {
                                prom_printf("clock_probe: Cannot find timer chip\n");
                                prom_halt();
                        }
                        continue;
                }

                err = prom_getproperty(node, "reg", (char *)clk_reg,
                                       sizeof(clk_reg));
                if(err == -1) {
                        prom_printf("clock_probe: Cannot get Mostek reg property\n");
                        prom_halt();
                }

                if(central_bus) {
                        prom_apply_fhc_ranges(central_bus->child, clk_reg, 1);
                        prom_apply_central_ranges(central_bus, clk_reg, 1);
                }
#ifdef CONFIG_PCI
                else if (ebus_chain) {
                        struct linux_ebus_device *edev;

                        for_each_ebusdev(edev, ebus)
                                if (edev->prom_node == node)
                                        break;
                        if (!edev) {
                                prom_printf("%s: Mostek not probed by EBUS\n",
                                            __FUNCTION__);
                                prom_halt();
                        }

                        if (check_region(edev->base_address[0],
                                         sizeof(struct mostek48t59))) {
                                prom_printf("%s: Can't get region %lx, %d\n",
                                            __FUNCTION__, edev->base_address[0],
                                            sizeof(struct mostek48t59));
                                prom_halt();
                        }
                        request_region(edev->base_address[0],
                                       sizeof(struct mostek48t59), "clock");

                        mstk48t59_regs = (struct mostek48t59 *)
                                                edev->base_address[0];
                        mstk48t02_regs = &mstk48t59_regs->regs;
                        break;
                }
#endif
                else {
                        prom_adjust_regs(clk_reg, 1,
                                         SBus_chain->sbus_ranges,
                                         SBus_chain->num_sbus_ranges);
                }

                if(model[5] == '0' && model[6] == '2') {
                        mstk48t02_regs = (struct mostek48t02 *)
                                sparc_alloc_io(clk_reg[0].phys_addr,
                                               (void *) 0, sizeof(*mstk48t02_regs),
                                               "clock", clk_reg[0].which_io, 0x0);
                } else if(model[5] == '0' && model[6] == '8') {
                        mstk48t08_regs = (struct mostek48t08 *)
                                sparc_alloc_io(clk_reg[0].phys_addr,
                                               (void *) 0, sizeof(*mstk48t08_regs),
                                               "clock", clk_reg[0].which_io, 0x0);
                        mstk48t02_regs = &mstk48t08_regs->regs;
                } else {
                        mstk48t59_regs = (struct mostek48t59 *)
                                sparc_alloc_io(clk_reg[0].phys_addr,
                                               (void *) 0, sizeof(*mstk48t59_regs),
                                               "clock", clk_reg[0].which_io, 0x0);
                        mstk48t02_regs = &mstk48t59_regs->regs;
                }
                break;
        }

        /* Report a low battery voltage condition. */
        if (has_low_battery())
                prom_printf("NVRAM: Low battery voltage!\n");

        /* Kick start the clock if it is completely stopped. */
        if (mstk48t02_regs->sec & MSTK_STOP)
                kick_start_clock();

        set_system_time();
        
        __restore_flags(flags);
}

#ifndef BCD_TO_BIN
#define BCD_TO_BIN(val) (((val)&15) + ((val)>>4)*10)
#endif

#ifndef BIN_TO_BCD
#define BIN_TO_BCD(val) ((((val)/10)<<4) + (val)%10)
#endif

extern void init_timers(void (*func)(int, void *, struct pt_regs *),
                        unsigned long *);

void __init time_init(void)
{
        /* clock_probe() is now done at end of [se]bus_init on sparc64
         * so that sbus, fhc and ebus bus information is probed and
         * available.
         */
        unsigned long clock;

        init_timers(timer_interrupt, &clock);
        timer_tick_offset = clock / HZ;
        timer_ticks_per_usec = clock / 1000000;
}

static __inline__ unsigned long do_gettimeoffset(void)
{
        unsigned long ticks;

        __asm__ __volatile__("
                rd      %%tick, %%g1
                add     %1, %%g1, %0
                sub     %0, %2, %0
"
                : "=r" (ticks)
                : "r" (timer_tick_offset), "r" (timer_tick_compare)
                : "g1", "g2");

        return ticks / timer_ticks_per_usec;
}

void do_gettimeofday(struct timeval *tv)
{
        /* Load doubles must be used on xtime so that what we get
         * is guarenteed to be atomic, this is why we can run this
         * with interrupts on full blast.  Don't touch this... -DaveM
         *
         * Note with time_t changes to the timeval type, I must now use
         * nucleus atomic quad 128-bit loads.
         */
        __asm__ __volatile__("
        sethi   %hi(timer_tick_offset), %g3
        sethi   %hi(xtime), %g2
        sethi   %hi(timer_tick_compare), %g1
        ldx     [%g3 + %lo(timer_tick_offset)], %g3
        or      %g2, %lo(xtime), %g2
        or      %g1, %lo(timer_tick_compare), %g1
1:      ldda    [%g2] 0x24, %o4
        membar  #LoadLoad | #MemIssue
        rd      %tick, %o1
        ldx     [%g1], %g7
        membar  #LoadLoad | #MemIssue
        ldda    [%g2] 0x24, %o2
        membar  #LoadLoad
        xor     %o4, %o2, %o2
        xor     %o5, %o3, %o3
        orcc    %o2, %o3, %g0
        bne,pn  %xcc, 1b
         sethi  %hi(lost_ticks), %o2
        sethi   %hi(timer_ticks_per_usec), %o3
        ldx     [%o2 + %lo(lost_ticks)], %o2
        add     %g3, %o1, %o1
        ldx     [%o3 + %lo(timer_ticks_per_usec)], %o3
        sub     %o1, %g7, %o1
        brz,pt  %o2, 1f
         udivx  %o1, %o3, %o1
        sethi   %hi(10000), %g2
        or      %g2, %lo(10000), %g2
        add     %o1, %g2, %o1
1:      sethi   %hi(1000000), %o2
        srlx    %o5, 32, %o5
        or      %o2, %lo(1000000), %o2
        add     %o5, %o1, %o5
        cmp     %o5, %o2
        bl,a,pn %xcc, 1f
         stx    %o4, [%o0 + 0x0]
        add     %o4, 0x1, %o4
        sub     %o5, %o2, %o5
        stx     %o4, [%o0 + 0x0]
1:      st      %o5, [%o0 + 0x8]");
}

void do_settimeofday(struct timeval *tv)
{
        cli();

        tv->tv_usec -= do_gettimeoffset();
        if(tv->tv_usec < 0) {
                tv->tv_usec += 1000000;
                tv->tv_sec--;
        }

        xtime = *tv;
        time_adjust = 0;                /* stop active adjtime() */
        time_status |= STA_UNSYNC;
        time_state = TIME_ERROR;        /* p. 24, (a) */
        time_maxerror = NTP_PHASE_LIMIT;
        time_esterror = NTP_PHASE_LIMIT;
        sti();
}

static int set_rtc_mmss(unsigned long nowtime)
{
        int real_seconds, real_minutes, mostek_minutes;
        struct mostek48t02 *regs = mstk48t02_regs;

        /* Not having a register set can lead to trouble. */
        if (!regs) 
                return -1;

        /* Read the current RTC minutes. */
        regs->creg |= MSTK_CREG_READ;
        mostek_minutes = MSTK_REG_MIN(regs);
        regs->creg &= ~MSTK_CREG_READ;

        /*
         * 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 - mostek_minutes) + 15)/30) & 1)
                real_minutes += 30;     /* correct for half hour time zone */
        real_minutes %= 60;

        if (abs(real_minutes - mostek_minutes) < 30) {
                regs->creg |= MSTK_CREG_WRITE;
                MSTK_SET_REG_SEC(regs,real_seconds);
                MSTK_SET_REG_MIN(regs,real_minutes);
                regs->creg &= ~MSTK_CREG_WRITE;
        } else
                return -1;

        return 0;
}