time.c

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/* $Id: time.c,v 1.57 2000/09/16 07:33:45 davem Exp $
 * linux/arch/sparc/kernel/time.c
 *
 * Copyright (C) 1995 David S. Miller ([e-mail])
 * Copyright (C) 1996 Thomas K. Dyas ([e-mail])
 *
 * Chris Davis ([e-mail]) 03/27/1998
 * Added support for the intersil on the sun4/4200
 *
 * Gleb Raiko ([e-mail]) 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/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/pci.h>
#include <linux/ioport.h>

#include <asm/oplib.h>
#include <asm/segment.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>

extern rwlock_t xtime_lock;

enum sparc_clock_type sp_clock_typ;
unsigned long mstk48t02_regs = 0UL;
static struct mostek48t08 *mstk48t08_regs = 0;
static int set_rtc_mmss(unsigned long);
static void sbus_do_settimeofday(struct timeval *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

static spinlock_t ticker_lock = SPIN_LOCK_UNLOCKED;

/* 32-bit Sparc specific profiling function. */
void sparc_do_profile(unsigned long pc, unsigned long o7)
{
	if(prof_buffer && current->pid) {
		extern int _stext;
		extern int __copy_user_begin, __copy_user_end;
		extern int __atomic_begin, __atomic_end;
		extern int __bzero_begin, __bzero_end;
		extern int __bitops_begin, __bitops_end;

		if ((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 = o7;

		pc -= (unsigned long) &_stext;
		pc >>= prof_shift;

		spin_lock(&ticker_lock);
		if(pc < prof_len)
			prof_buffer[pc]++;
		else
			prof_buffer[prof_len - 1]++;
		spin_unlock(&ticker_lock);
	}
}

__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
 */
void timer_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	/* last time the cmos clock got updated */
	static long last_rtc_update=0;

#ifndef CONFIG_SMP
	if(!user_mode(regs))
		sparc_do_profile(regs->pc, regs->u_regs[UREG_RETPC]);
#endif

#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();

	write_lock(&xtime_lock);

	do_timer(regs);

	/* 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 */
	}
	write_unlock(&xtime_lock);
}

/* 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 ");

	/* 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 __inline__ int has_low_battery(void)
{
	struct mostek48t02 *regs = (struct mostek48t02 *)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 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), 0);
		mstk48t08_regs = 0;  /* To catch weirdness */
		intersil_clock = 0;  /* 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 = 0;  /* 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
}

/* Probe for the mostek real time clock chip. */
static __inline__ void clock_probe(void)
{
	struct linux_prom_registers clk_reg[2];
	char model[128];
	register int node, cpuunit, bootbus;
	struct resource r;

	cpuunit = bootbus = 0;
	memset(&r, 0, sizeof(r));

	/* Determine the correct starting PROM node for the probe. */
	node = prom_getchild(prom_root_node);
	switch (sparc_cpu_model) {
	case sun4c:
		break;
	case sun4m:
		node = prom_getchild(prom_searchsiblings(node, "obio"));
		break;
	case sun4d:
		node = prom_getchild(bootbus = prom_searchsiblings(prom_getchild(cpuunit = prom_searchsiblings(node, "cpu-unit")), "bootbus"));
		break;
	default:
		prom_printf("CLOCK: Unsupported architecture!\n");
		prom_halt();
	}

	/* Find the PROM node describing the real time clock. */
	sp_clock_typ = MSTK_INVALID;
	node = prom_searchsiblings(node,"eeprom");
	if (!node) {
		prom_printf("CLOCK: No clock found!\n");