Eleminate mips_cpu and move it into cpu_data.

[linux-2.6/linux-mips.git] / arch / mips / kernel / time.c

/*
 * Copyright 2001 MontaVista Software Inc.
 * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
 *
 * Common time service routines for MIPS machines. See
 * Documents/mips/README.txt.
 *
 * 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.
 */
#include <linux/config.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/param.h>
#include <linux/time.h>
#include <linux/smp.h>
#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/module.h>

#include <asm/bootinfo.h>
#include <asm/cpu.h>
#include <asm/time.h>
#include <asm/hardirq.h>
#include <asm/div64.h>

/* This is for machines which generate the exact clock. */
#define USECS_PER_JIFFY (1000000/HZ)
#define USECS_PER_JIFFY_FRAC ((u32)((1000000ULL << 32) / HZ))

#define TICK_SIZE       (tick_nsec / 1000)

u64 jiffies_64;

/*
 * forward reference
 */
extern rwlock_t xtime_lock;
extern volatile unsigned long wall_jiffies;

spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;

/*
 * whether we emulate local_timer_interrupts for SMP machines.
 */
int emulate_local_timer_interrupt;

/*
 * By default we provide the null RTC ops
 */
static unsigned long null_rtc_get_time(void)
{
        return mktime(2000, 1, 1, 0, 0, 0);
}

static int null_rtc_set_time(unsigned long sec)
{
        return 0;
}

unsigned long (*rtc_get_time)(void) = null_rtc_get_time;
int (*rtc_set_time)(unsigned long) = null_rtc_set_time;


/*
 * This version of gettimeofday has microsecond resolution and better than
 * microsecond precision on fast machines with cycle counter.
 */
void do_gettimeofday(struct timeval *tv)
{
        unsigned long flags;
        unsigned long usec, sec;

        read_lock_irqsave(&xtime_lock, flags);
        usec = do_gettimeoffset();
        {
                unsigned long lost = jiffies - wall_jiffies;
                if (lost)
                        usec += lost * (1000000 / HZ);
        }
        sec = xtime.tv_sec;
        usec += (xtime.tv_nsec / 1000);
        read_unlock_irqrestore(&xtime_lock, flags);

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

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

void do_settimeofday(struct timeval *tv)
{
        write_lock_irq(&xtime_lock);
        /*
         * 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!
         */
        tv->tv_usec -= do_gettimeoffset();
        tv->tv_usec -= (jiffies - wall_jiffies) * (1000000 / HZ);

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

        xtime.tv_sec = tv->tv_sec;
        xtime.tv_nsec = (tv->tv_usec * 1000);
        time_adjust = 0;                /* stop active adjtime() */
        time_status |= STA_UNSYNC;
        time_maxerror = NTP_PHASE_LIMIT;
        time_esterror = NTP_PHASE_LIMIT;
        write_unlock_irq(&xtime_lock);
}


/*
 * Gettimeoffset routines.  These routines returns the time duration
 * since last timer interrupt in usecs.
 *
 * If the exact CPU counter frequency is known, use fixed_rate_gettimeoffset.
 * Otherwise use calibrate_gettimeoffset()
 *
 * If the CPU does not have counter register all, you can either supply
 * your own gettimeoffset() routine, or use null_gettimeoffset() routines,
 * which gives the same resolution as HZ.
 */


/* This is for machines which generate the exact clock. */
#define USECS_PER_JIFFY (1000000/HZ)

/* usecs per counter cycle, shifted to left by 32 bits */
static unsigned int sll32_usecs_per_cycle=0;

/* how many counter cycles in a jiffy */
static unsigned long cycles_per_jiffy=0;

/* Cycle counter value at the previous timer interrupt.. */
static unsigned int timerhi, timerlo;

/* last time when xtime and rtc are sync'ed up */
static long last_rtc_update;

/* the function pointer to one of the gettimeoffset funcs*/
unsigned long (*do_gettimeoffset)(void) = null_gettimeoffset;

unsigned long null_gettimeoffset(void)
{
        return 0;
}

unsigned long fixed_rate_gettimeoffset(void)
{
        u32 count;
        unsigned long res;

        /* Get last timer tick in absolute kernel time */
        count = read_c0_count();

        /* .. relative to previous jiffy (32 bits is enough) */
        count -= timerlo;

        __asm__("multu\t%1,%2\n\t"
                "mfhi\t%0"
                :"=r" (res)
                :"r" (count),
                 "r" (sll32_usecs_per_cycle));

        /*
         * Due to possible jiffies inconsistencies, we need to check
         * the result so that we'll get a timer that is monotonic.
         */
        if (res >= USECS_PER_JIFFY)
                res = USECS_PER_JIFFY-1;

        return res;
}

/*
 * Cached "1/(clocks per usec)*2^32" value.
 * It has to be recalculated once each jiffy.
 */
static unsigned long cached_quotient;

/* Last jiffy when calibrate_divXX_gettimeoffset() was called. */
static unsigned long last_jiffies = 0;


/*
 * This is copied from dec/time.c:do_ioasic_gettimeoffset() by Mercij.
 */
unsigned long calibrate_div32_gettimeoffset(void)
{
        u32 count;
        unsigned long res, tmp;
        unsigned long quotient;

        tmp = jiffies;

        quotient = cached_quotient;

        if (last_jiffies != tmp) {
                last_jiffies = tmp;
                if (last_jiffies != 0) {
                        unsigned long r0;
                        do_div64_32(r0, timerhi, timerlo, tmp);
                        do_div64_32(quotient, USECS_PER_JIFFY,
                                    USECS_PER_JIFFY_FRAC, r0);
                        cached_quotient = quotient;
                }
        }

        /* Get last timer tick in absolute kernel time */
        count = read_c0_count();

        /* .. relative to previous jiffy (32 bits is enough) */
        count -= timerlo;

        __asm__("multu  %2,%3"
                : "=l" (tmp), "=h" (res)
                : "r" (count), "r" (quotient));

        /*
         * Due to possible jiffies inconsistencies, we need to check
         * the result so that we'll get a timer that is monotonic.
         */
        if (res >= USECS_PER_JIFFY)
                res = USECS_PER_JIFFY - 1;

        return res;
}

unsigned long calibrate_div64_gettimeoffset(void)
{
        u32 count;
        unsigned long res, tmp;
        unsigned long quotient;

        tmp = jiffies;

        quotient = cached_quotient;

        if (tmp && last_jiffies != tmp) {
                last_jiffies = tmp;
                __asm__(".set\tnoreorder\n\t"
                ".set\tnoat\n\t"
                ".set\tmips3\n\t"
                "lwu\t%0,%2\n\t"
                "dsll32\t$1,%1,0\n\t"
                "or\t$1,$1,%0\n\t"
                "ddivu\t$0,$1,%3\n\t"
                "mflo\t$1\n\t"
                "dsll32\t%0,%4,0\n\t"
                "nop\n\t"
                "ddivu\t$0,%0,$1\n\t"
                "mflo\t%0\n\t"
                ".set\tmips0\n\t"
                ".set\tat\n\t"
                ".set\treorder"
                :"=&r" (quotient)
                :"r" (timerhi),
                 "m" (timerlo),
                 "r" (tmp),
                 "r" (USECS_PER_JIFFY));
                cached_quotient = quotient;
        }

        /* Get last timer tick in absolute kernel time */
        count = read_c0_count();

        /* .. relative to previous jiffy (32 bits is enough) */
        count -= timerlo;

        __asm__("multu\t%1,%2\n\t"
                "mfhi\t%0"
                :"=r" (res)
                :"r" (count),
                 "r" (quotient));

        /*
         * Due to possible jiffies inconsistencies, we need to check
         * the result so that we'll get a timer that is monotonic.
         */
        if (res >= USECS_PER_JIFFY)
                res = USECS_PER_JIFFY-1;

        return res;
}


/*
 * local_timer_interrupt() does profiling and process accounting
 * on a per-CPU basis.
 *
 * In UP mode, it is invoked from the (global) timer_interrupt.
 *
 * In SMP mode, it might invoked by per-CPU timer interrupt, or
 * a broadcasted inter-processor interrupt which itself is triggered
 * by the global timer interrupt.
 */
void local_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        if (!user_mode(regs)) {
                if (prof_buffer && current->pid) {
                        extern int _stext;
                        unsigned long pc = regs->cp0_epc;

                        pc -= (unsigned long) &_stext;
                        pc >>= prof_shift;
                        /*
                         * Dont ignore out-of-bounds pc values silently,
                         * put them into the last histogram slot, so if
                         * present, they will show up as a sharp peak.
                         */
                        if (pc > prof_len-1)
                        pc = prof_len-1;
                        atomic_inc((atomic_t *)&prof_buffer[pc]);
                }
        }

#ifdef CONFIG_SMP
        /* in UP mode, update_process_times() is invoked by do_timer() */
        update_process_times(user_mode(regs));
#endif
}

/*
 * high-level timer interrupt service routines.  This function
 * is set as irqaction->handler and is invoked through do_IRQ.
 */
void timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        if (current_cpu_data.options & MIPS_CPU_COUNTER) {
                unsigned int count;

                /*
                 * The cycle counter is only 32 bit which is good for about
                 * a minute at current count rates of upto 150MHz or so.
                 */
                count = read_c0_count();
                timerhi += (count < timerlo);   /* Wrap around */
                timerlo = count;

                /*
                 * set up for next timer interrupt - no harm if the machine
                 * is using another timer interrupt source.
                 * Note that writing to COMPARE register clears the interrupt
                 */
                write_c0_compare(
                                          count + cycles_per_jiffy);

        }

        /*
         * call the generic timer interrupt handling
         */
        do_timer(regs);

        /*
         * If we have an externally synchronized Linux clock, then update
         * CMOS clock accordingly every ~11 minutes. rtc_set_time() has to be
         * called as close as possible to 500 ms before the new second starts.
         */
        read_lock (&xtime_lock);
        if ((time_status & STA_UNSYNC) == 0 &&
            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 (rtc_set_time(xtime.tv_sec) == 0) {
                        last_rtc_update = xtime.tv_sec;
                } else {
                        last_rtc_update = xtime.tv_sec - 600;
                        /* do it again in 60 s */
                }
        }
        read_unlock (&xtime_lock);

        /*
         * If jiffies has overflowed in this timer_interrupt we must
         * update the timer[hi]/[lo] to make fast gettimeoffset funcs
         * quotient calc still valid. -arca
         */
        if (!jiffies) {
                timerhi = timerlo = 0;
        }

#if !defined(CONFIG_SMP)
        /*
         * In UP mode, we call local_timer_interrupt() to do profiling
         * and process accouting.
         *
         * In SMP mode, local_timer_interrupt() is invoked by appropriate
         * low-level local timer interrupt handler.
         */
        local_timer_interrupt(0, NULL, regs);

#else   /* CONFIG_SMP */

        if (emulate_local_timer_interrupt) {
                /*
                 * this is the place where we send out inter-process
                 * interrupts and let each CPU do its own profiling
                 * and process accouting.
                 *
                 * Obviously we need to call local_timer_interrupt() for
                 * the current CPU too.
                 */
                panic("Not implemented yet!!!");
        }
#endif  /* CONFIG_SMP */
}

asmlinkage void ll_timer_interrupt(int irq, struct pt_regs *regs)
{
        int cpu = smp_processor_id();

        irq_enter();
        kstat_cpu(cpu).irqs[irq]++;

        /* we keep interrupt disabled all the time */
        timer_interrupt(irq, NULL, regs);

        irq_exit();

        if (softirq_pending(cpu))
                do_softirq();
}

asmlinkage void ll_local_timer_interrupt(int irq, struct pt_regs *regs)
{
        int cpu = smp_processor_id();

        irq_enter();
        kstat_cpu(cpu).irqs[irq]++;

        /* we keep interrupt disabled all the time */
        local_timer_interrupt(irq, NULL, regs);

        irq_exit();

        if (softirq_pending(cpu))
                do_softirq();
}

/*
 * time_init() - it does the following things.
 *
 * 1) board_time_init() -
 *      a) (optional) set up RTC routines,
 *      b) (optional) calibrate and set the mips_counter_frequency
 *          (only needed if you intended to use fixed_rate_gettimeoffset
 *           or use cpu counter as timer interrupt source)
 * 2) setup xtime based on rtc_get_time().
 * 3) choose a appropriate gettimeoffset routine.
 * 4) calculate a couple of cached variables for later usage
 * 5) board_timer_setup() -
 *      a) (optional) over-write any choices made above by time_init().
 *      b) machine specific code should setup the timer irqaction.
 *      c) enable the timer interrupt
 */

void (*board_time_init)(void) = NULL;
void (*board_timer_setup)(struct irqaction *irq) = NULL;

unsigned int mips_counter_frequency = 0;

static struct irqaction timer_irqaction = {
        timer_interrupt,
        SA_INTERRUPT,
        0,
        "timer",
        NULL,
        NULL
};

void __init time_init(void)
{
        if (board_time_init)
                board_time_init();

        xtime.tv_sec = rtc_get_time();
        xtime.tv_nsec = 0;

        /* choose appropriate gettimeoffset routine */
        if (!(current_cpu_data.options & MIPS_CPU_COUNTER)) {
                /* no cpu counter - sorry */
                do_gettimeoffset = null_gettimeoffset;
        } else if (mips_counter_frequency != 0) {
                /* we have cpu counter and know counter frequency! */
                do_gettimeoffset = fixed_rate_gettimeoffset;
        } else if ((current_cpu_data.isa_level == MIPS_CPU_ISA_M32) ||
                   (current_cpu_data.isa_level == MIPS_CPU_ISA_I) ||
                   (current_cpu_data.isa_level == MIPS_CPU_ISA_II) ) {
                /* we need to calibrate the counter but we don't have
                 * 64-bit division. */
                do_gettimeoffset = calibrate_div32_gettimeoffset;
        } else {
                /* we need to calibrate the counter but we *do* have
                 * 64-bit division. */
                do_gettimeoffset = calibrate_div64_gettimeoffset;
        }

        /* caclulate cache parameters */
        if (mips_counter_frequency) {
                u32 count;

                cycles_per_jiffy = mips_counter_frequency / HZ;

                /* sll32_usecs_per_cycle = 10^6 * 2^32 / mips_counter_freq */
                /* any better way to do this? */
                sll32_usecs_per_cycle = mips_counter_frequency / 100000;
                sll32_usecs_per_cycle = 0xffffffff / sll32_usecs_per_cycle;
                sll32_usecs_per_cycle *= 10;

                /*
                 * For those using cpu counter as timer,  this sets up the
                 * first interrupt
                 */
                count = read_c0_count();
                write_c0_compare(
                                          count + cycles_per_jiffy);
        }

        /*
         * Call board specific timer interrupt setup.
         *
         * this pointer must be setup in machine setup routine.
         *
         * Even if the machine choose to use low-level timer interrupt,
         * it still needs to setup the timer_irqaction.
         * In that case, it might be better to set timer_irqaction.handler
         * to be NULL function so that we are sure the high-level code
         * is not invoked accidentally.
         */
        board_timer_setup(&timer_irqaction);
}

#define FEBRUARY                2
#define STARTOFTIME             1970
#define SECDAY                  86400L
#define SECYR                   (SECDAY * 365)
#define leapyear(year)          ((year) % 4 == 0)
#define days_in_year(a)         (leapyear(a) ? 366 : 365)
#define days_in_month(a)        (month_days[(a) - 1])

static int month_days[12] = {
        31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};

void to_tm(unsigned long tim, struct rtc_time * tm)
{
        long hms, day, gday;
        int i;

        gday = day = tim / SECDAY;
        hms = tim % SECDAY;

        /* Hours, minutes, seconds are easy */
        tm->tm_hour = hms / 3600;
        tm->tm_min = (hms % 3600) / 60;
        tm->tm_sec = (hms % 3600) % 60;

        /* Number of years in days */
        for (i = STARTOFTIME; day >= days_in_year(i); i++)
        day -= days_in_year(i);
        tm->tm_year = i;

        /* Number of months in days left */
        if (leapyear(tm->tm_year))
        days_in_month(FEBRUARY) = 29;
        for (i = 1; day >= days_in_month(i); i++)
        day -= days_in_month(i);
        days_in_month(FEBRUARY) = 28;
        tm->tm_mon = i-1;       /* tm_mon starts from 0 to 11 */

        /* Days are what is left over (+1) from all that. */
        tm->tm_mday = day + 1;

        /*
         * Determine the day of week
         */
        tm->tm_wday = (gday + 4) % 7; /* 1970/1/1 was Thursday */
}

EXPORT_SYMBOL(rtc_lock);