/* linux/arch/sparc/kernel/time.c
 *
 * Copyright (C) 1995 David S. Miller (davem@davemloft.net)
 * 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/rtc.h>
#include <linux/rtc/m48t59.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/ioport.h>
#include <linux/profile.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>

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

#include "irq.h"

DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);

static int set_rtc_mmss(unsigned long);
static int sbus_do_settimeofday(struct timespec *tv);

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[];

        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 = regs->u_regs[UREG_RETPC];
        return pc;
}

EXPORT_SYMBOL(profile_pc);

__volatile__ unsigned int *master_l10_counter;

/*
 * 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)

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

#ifndef CONFIG_SMP
        profile_tick(CPU_PROFILING);
#endif

        /* Protect counter clear so that do_gettimeoffset works */
        write_seqlock(&xtime_lock);

        clear_clock_irq();

        do_timer(1);

        /* 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);

#ifndef CONFIG_SMP
        update_process_times(user_mode(get_irq_regs()));
#endif
        return IRQ_HANDLED;
}

static unsigned char mostek_read_byte(struct device *dev, u32 ofs)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct m48t59_plat_data *pdata = pdev->dev.platform_data;

        return readb(pdata->ioaddr + ofs);
}

static void mostek_write_byte(struct device *dev, u32 ofs, u8 val)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct m48t59_plat_data *pdata = pdev->dev.platform_data;

        writeb(val, pdata->ioaddr + ofs);
}

static struct m48t59_plat_data m48t59_data = {
        .read_byte = mostek_read_byte,
        .write_byte = mostek_write_byte,
};

/* resource is set at runtime */
static struct platform_device m48t59_rtc = {
        .name           = "rtc-m48t59",
        .id             = 0,
        .num_resources  = 1,
        .dev    = {
                .platform_data = &m48t59_data,
        },
};

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

        if (!model)
                return -ENODEV;

        m48t59_rtc.resource = &op->resource[0];
        if (!strcmp(model, "mk48t02")) {
                /* Map the clock register io area read-only */
                m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
                                                2048, "rtc-m48t59");
                m48t59_data.type = M48T59RTC_TYPE_M48T02;
        } else if (!strcmp(model, "mk48t08")) {
                m48t59_data.ioaddr = of_ioremap(&op->resource[0], 0,
                                                8192, "rtc-m48t59");
                m48t59_data.type = M48T59RTC_TYPE_M48T08;
        } else
                return -ENODEV;

        if (platform_device_register(&m48t59_rtc) < 0)
                printk(KERN_ERR "Registering RTC device failed\n");

        return 0;
}

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

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


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

static void __init sbus_time_init(void)
{

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

        sparc_init_timers(timer_interrupt);
        
        /* 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)
{
        unsigned long val = *master_l10_counter;
        unsigned long usec = (val >> 10) & 0x1fffff;

        /* Limit hit?  */
        if (val & 0x80000000)
                usec += 1000000 / HZ;

        return usec;
}

/* 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, 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 {
                seq = read_seqbegin_irqsave(&xtime_lock, flags);
                usec = do_gettimeoffset();

                /*
                 * 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);

                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();

        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;
}

static int set_rtc_mmss(unsigned long secs)
{
        struct rtc_device *rtc = rtc_class_open("rtc0");
        int err = -1;

        if (rtc) {
                err = rtc_set_mmss(rtc, secs);
                rtc_class_close(rtc);
        }

        return err;
}