[PATCH] simplify update_times (avoid jiffies/jiffies_64 aliasing problem)

[deliverable/linux.git] / arch / sparc / kernel / time.c

/* $Id: time.c,v 1.60 2002/01/23 14:33:55 davem Exp $
 * linux/arch/sparc/kernel/time.c
 *
 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 * Copyright (C) 1996 Thomas K. Dyas (tdyas@eden.rutgers.edu)
 *
 * Chris Davis (cdavis@cois.on.ca) 03/27/1998
 * Added support for the intersil on the sun4/4200
 *
 * Gleb Raiko (rajko@mech.math.msu.su) 08/18/1998
 * Support for MicroSPARC-IIep, PCI CPU.
 *
 * This file handles the Sparc specific time handling details.
 *
 * 1997-09-10   Updated NTP code according to technical memorandum Jan '96
 *              "A Kernel Model for Precision Timekeeping" by Dave Mills
 */
#include <linux/errno.h>
#include <linux/module.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/time.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/profile.h>

#include <asm/oplib.h>
#include <asm/timer.h>
#include <asm/mostek.h>
#include <asm/system.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/idprom.h>
#include <asm/machines.h>
#include <asm/sun4paddr.h>
#include <asm/page.h>
#include <asm/pcic.h>
#include <asm/of_device.h>

extern unsigned long wall_jiffies;

DEFINE_SPINLOCK(rtc_lock);
enum sparc_clock_type sp_clock_typ;
DEFINE_SPINLOCK(mostek_lock);
void __iomem *mstk48t02_regs = NULL;
static struct mostek48t08 __iomem *mstk48t08_regs = NULL;
static int set_rtc_mmss(unsigned long);
static int sbus_do_settimeofday(struct timespec *tv);

#ifdef CONFIG_SUN4
struct intersil *intersil_clock;
#define intersil_cmd(intersil_reg, intsil_cmd) intersil_reg->int_cmd_reg = \
        (intsil_cmd)

#define intersil_intr(intersil_reg, intsil_cmd) intersil_reg->int_intr_reg = \
        (intsil_cmd)

#define intersil_start(intersil_reg) intersil_cmd(intersil_reg, \
        ( INTERSIL_START | INTERSIL_32K | INTERSIL_NORMAL | INTERSIL_24H |\
          INTERSIL_INTR_ENABLE))

#define intersil_stop(intersil_reg) intersil_cmd(intersil_reg, \
        ( INTERSIL_STOP | INTERSIL_32K | INTERSIL_NORMAL | INTERSIL_24H |\
          INTERSIL_INTR_ENABLE))

#define intersil_read_intr(intersil_reg, towhere) towhere = \
        intersil_reg->int_intr_reg

#endif

unsigned long profile_pc(struct pt_regs *regs)
{
        extern char __copy_user_begin[], __copy_user_end[];
        extern char __atomic_begin[], __atomic_end[];
        extern char __bzero_begin[], __bzero_end[];
        extern char __bitops_begin[], __bitops_end[];

        unsigned long pc = regs->pc;

        if (in_lock_functions(pc) ||
            (pc >= (unsigned long) __copy_user_begin &&
             pc < (unsigned long) __copy_user_end) ||
            (pc >= (unsigned long) __atomic_begin &&
             pc < (unsigned long) __atomic_end) ||
            (pc >= (unsigned long) __bzero_begin &&
             pc < (unsigned long) __bzero_end) ||
            (pc >= (unsigned long) __bitops_begin &&
             pc < (unsigned long) __bitops_end))
                pc = regs->u_regs[UREG_RETPC];
        return pc;
}

__volatile__ unsigned int *master_l10_counter;
__volatile__ unsigned int *master_l10_limit;

/*
 * timer_interrupt() needs to keep up the real-time clock,
 * as well as call the "do_timer()" routine every clocktick
 */

#define TICK_SIZE (tick_nsec / 1000)

irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
        /* last time the cmos clock got updated */
        static long last_rtc_update;

#ifndef CONFIG_SMP
        profile_tick(CPU_PROFILING, regs);
#endif

        /* Protect counter clear so that do_gettimeoffset works */
        write_seqlock(&xtime_lock);
#ifdef CONFIG_SUN4
        if((idprom->id_machtype == (SM_SUN4 | SM_4_260)) ||
           (idprom->id_machtype == (SM_SUN4 | SM_4_110))) {
                int temp;
                intersil_read_intr(intersil_clock, temp);
                /* re-enable the irq */
                enable_pil_irq(10);
        }
#endif
        clear_clock_irq();

        do_timer(1);
#ifndef CONFIG_SMP
        update_process_times(user_mode(regs));
#endif


        /* Determine when to update the Mostek clock. */
        if (ntp_synced() &&
            xtime.tv_sec > last_rtc_update + 660 &&
            (xtime.tv_nsec / 1000) >= 500000 - ((unsigned) TICK_SIZE) / 2 &&
            (xtime.tv_nsec / 1000) <= 500000 + ((unsigned) TICK_SIZE) / 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 */
        }
        write_sequnlock(&xtime_lock);

        return IRQ_HANDLED;
}

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

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

        spin_lock_irq(&mostek_lock);

        /* 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;

        spin_unlock_irq(&mostek_lock);

        /* 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");

        spin_lock_irq(&mostek_lock);

        /* 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;

        spin_unlock_irq(&mostek_lock);

        /* 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");

                spin_lock_irq(&mostek_lock);
                regs->creg |= MSTK_CREG_WRITE;
                regs->hour &= ~MSTK_KICK_START;
                regs->creg &= ~MSTK_CREG_WRITE;
                spin_unlock_irq(&mostek_lock);
        }

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

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

        spin_lock_irq(&mostek_lock);
        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. */
        spin_unlock_irq(&mostek_lock);

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

static void __init mostek_set_system_time(void)
{
        unsigned int year, mon, day, hour, min, sec;
        struct mostek48t02 *mregs;

        mregs = (struct mostek48t02 *)mstk48t02_regs;
        if(!mregs) {
                prom_printf("Something wrong, clock regs not mapped yet.\n");
                prom_halt();
        }               
        spin_lock_irq(&mostek_lock);
        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_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
        set_normalized_timespec(&wall_to_monotonic,
                                -xtime.tv_sec, -xtime.tv_nsec);
        mregs->creg &= ~MSTK_CREG_READ;
        spin_unlock_irq(&mostek_lock);
}

/* Probe for the real time clock chip on Sun4 */
static __inline__ void sun4_clock_probe(void)
{
#ifdef CONFIG_SUN4
        int temp;
        struct resource r;

        memset(&r, 0, sizeof(r));
        if( idprom->id_machtype == (SM_SUN4 | SM_4_330) ) {
                sp_clock_typ = MSTK48T02;
                r.start = sun4_clock_physaddr;
                mstk48t02_regs = sbus_ioremap(&r, 0,
                                       sizeof(struct mostek48t02), NULL);
                mstk48t08_regs = NULL;  /* To catch weirdness */
                intersil_clock = NULL;  /* just in case */

                /* Kick start the clock if it is completely stopped. */
                if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
                        kick_start_clock();
        } else if( idprom->id_machtype == (SM_SUN4 | SM_4_260)) {
                /* intersil setup code */
                printk("Clock: INTERSIL at %8x ",sun4_clock_physaddr);
                sp_clock_typ = INTERSIL;
                r.start = sun4_clock_physaddr;
                intersil_clock = (struct intersil *) 
                    sbus_ioremap(&r, 0, sizeof(*intersil_clock), "intersil");
                mstk48t02_regs = 0;  /* just be sure */
                mstk48t08_regs = NULL;  /* ditto */
                /* initialise the clock */

                intersil_intr(intersil_clock,INTERSIL_INT_100HZ);

                intersil_start(intersil_clock);

                intersil_read_intr(intersil_clock, temp);
                while (!(temp & 0x80))
                        intersil_read_intr(intersil_clock, temp);

                intersil_read_intr(intersil_clock, temp);
                while (!(temp & 0x80))
                        intersil_read_intr(intersil_clock, temp);

                intersil_stop(intersil_clock);

        }
#endif
}

#ifndef CONFIG_SUN4
static int __devinit clock_probe(struct of_device *op, const struct of_device_id *match)
{
        struct device_node *dp = op->node;
        char *model = of_get_property(dp, "model", NULL);

        if (!model)
                return -ENODEV;

        if (!strcmp(model, "mk48t02")) {
                sp_clock_typ = MSTK48T02;

                /* Map the clock register io area read-only */
                mstk48t02_regs = of_ioremap(&op->resource[0], 0,
                                            sizeof(struct mostek48t02),
                                            "mk48t02");
                mstk48t08_regs = NULL;  /* To catch weirdness */
        } else if (!strcmp(model, "mk48t08")) {
                sp_clock_typ = MSTK48T08;
                mstk48t08_regs = of_ioremap(&op->resource[0], 0,
                                            sizeof(struct mostek48t08),
                                            "mk48t08");

                mstk48t02_regs = &mstk48t08_regs->regs;
        } else
                return -ENODEV;

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

        /* Kick start the clock if it is completely stopped. */
        if (mostek_read(mstk48t02_regs + MOSTEK_SEC) & MSTK_STOP)
                kick_start_clock();

        mostek_set_system_time();

        return 0;
}

static struct of_device_id clock_match[] = {
        {
                .name = "eeprom",
        },
        {},
};

static struct of_platform_driver clock_driver = {
        .name           = "clock",
        .match_table    = clock_match,
        .probe          = clock_probe,
};


/* Probe for the mostek real time clock chip. */
static int __init clock_init(void)
{
        return of_register_driver(&clock_driver, &of_bus_type);
}

/* Must be after subsys_initcall() so that busses are probed.  Must
 * be before device_initcall() because things like the RTC driver
 * need to see the clock registers.
 */
fs_initcall(clock_init);
#endif /* !CONFIG_SUN4 */

void __init sbus_time_init(void)
{

        BTFIXUPSET_CALL(bus_do_settimeofday, sbus_do_settimeofday, BTFIXUPCALL_NORM);
        btfixup();

        if (ARCH_SUN4)
                sun4_clock_probe();

        sparc_init_timers(timer_interrupt);
        
#ifdef CONFIG_SUN4
        if(idprom->id_machtype == (SM_SUN4 | SM_4_330)) {
                mostek_set_system_time();
        } else if(idprom->id_machtype == (SM_SUN4 | SM_4_260) ) {
                /* initialise the intersil on sun4 */
                unsigned int year, mon, day, hour, min, sec;
                int temp;
                struct intersil *iregs;

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

                intersil_intr(intersil_clock,INTERSIL_INT_100HZ);
                disable_pil_irq(10);
                intersil_stop(iregs);
                intersil_read_intr(intersil_clock, temp);

                temp = iregs->clk.int_csec;

                sec = iregs->clk.int_sec;
                min = iregs->clk.int_min;
                hour = iregs->clk.int_hour;
                day = iregs->clk.int_day;
                mon = iregs->clk.int_month;
                year = MSTK_CVT_YEAR(iregs->clk.int_year);

                enable_pil_irq(10);
                intersil_start(iregs);

                xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
                xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
                set_normalized_timespec(&wall_to_monotonic,
                                       -xtime.tv_sec, -xtime.tv_nsec);
                printk("%u/%u/%u %u:%u:%u\n",day,mon,year,hour,min,sec);
        }
#endif

        /* Now that OBP ticker has been silenced, it is safe to enable IRQ. */
        local_irq_enable();
}

void __init time_init(void)
{
#ifdef CONFIG_PCI
        extern void pci_time_init(void);
        if (pcic_present()) {
                pci_time_init();
                return;
        }
#endif
        sbus_time_init();
}

static inline unsigned long do_gettimeoffset(void)
{
        return (*master_l10_counter >> 10) & 0x1fffff;
}

/*
 * Returns nanoseconds
 * XXX This is a suboptimal implementation.
 */
unsigned long long sched_clock(void)
{
        return (unsigned long long)jiffies * (1000000000 / HZ);
}

/* Ok, my cute asm atomicity trick doesn't work anymore.
 * There are just too many variables that need to be protected
 * now (both members of xtime, wall_jiffies, et al.)
 */
void do_gettimeofday(struct timeval *tv)
{
        unsigned long flags;
        unsigned long seq;
        unsigned long usec, sec;
        unsigned long max_ntp_tick = tick_usec - tickadj;

        do {
                unsigned long lost;

                seq = read_seqbegin_irqsave(&xtime_lock, flags);
                usec = do_gettimeoffset();
                lost = jiffies - wall_jiffies;

                /*
                 * If time_adjust is negative then NTP is slowing the clock
                 * so make sure not to go into next possible interval.
                 * Better to lose some accuracy than have time go backwards..
                 */
                if (unlikely(time_adjust < 0)) {
                        usec = min(usec, max_ntp_tick);

                        if (lost)
                                usec += lost * max_ntp_tick;
                }
                else if (unlikely(lost))
                        usec += lost * tick_usec;

                sec = xtime.tv_sec;
                usec += (xtime.tv_nsec / 1000);
        } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));

        while (usec >= 1000000) {
                usec -= 1000000;
                sec++;
        }

        tv->tv_sec = sec;
        tv->tv_usec = usec;
}

EXPORT_SYMBOL(do_gettimeofday);

int do_settimeofday(struct timespec *tv)
{
        int ret;

        write_seqlock_irq(&xtime_lock);
        ret = bus_do_settimeofday(tv);
        write_sequnlock_irq(&xtime_lock);
        clock_was_set();
        return ret;
}

EXPORT_SYMBOL(do_settimeofday);

static int sbus_do_settimeofday(struct timespec *tv)
{
        time_t wtm_sec, sec = tv->tv_sec;
        long wtm_nsec, nsec = tv->tv_nsec;

        if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
                return -EINVAL;

        /*
         * This is revolting. We need to set "xtime" correctly. However, the
         * value in this location is the value at the most recent update of
         * wall time.  Discover what correction gettimeofday() would have
         * made, and then undo it!
         */
        nsec -= 1000 * (do_gettimeoffset() +
                        (jiffies - wall_jiffies) * (USEC_PER_SEC / HZ));

        wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
        wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);

        set_normalized_timespec(&xtime, sec, nsec);
        set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);

        ntp_clear();
        return 0;
}

/*
 * BUG: This routine does not handle hour overflow properly; it just
 *      sets the minutes. Usually you won't notice until after reboot!
 */
static int set_rtc_mmss(unsigned long nowtime)
{
        int real_seconds, real_minutes, mostek_minutes;
        struct mostek48t02 *regs = (struct mostek48t02 *)mstk48t02_regs;
        unsigned long flags;
#ifdef CONFIG_SUN4
        struct intersil *iregs = intersil_clock;
        int temp;
#endif

        /* Not having a register set can lead to trouble. */
        if (!regs) {
#ifdef CONFIG_SUN4
                if(!iregs)
                return -1;
                else {
                        temp = iregs->clk.int_csec;

                        mostek_minutes = iregs->clk.int_min;

                        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) {
                                intersil_stop(iregs);
                                iregs->clk.int_sec=real_seconds;
                                iregs->clk.int_min=real_minutes;
                                intersil_start(iregs);
                        } else {
                                printk(KERN_WARNING
                               "set_rtc_mmss: can't update from %d to %d\n",
                                       mostek_minutes, real_minutes);
                                return -1;
                        }
                        
                        return 0;
                }
#endif
        }

        spin_lock_irqsave(&mostek_lock, flags);
        /* 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;
                spin_unlock_irqrestore(&mostek_lock, flags);
                return 0;
        } else {
                spin_unlock_irqrestore(&mostek_lock, flags);
                return -1;
        }
}