arch/cris/arch-v32/kernel/time.c - maze/linux - Git at Google

 /*
  *  linux/arch/cris/arch-v32/kernel/time.c
  *
  *  Copyright (C) 2003-2007 Axis Communications AB
  *
  */

 #include <linux/timex.h>
 #include <linux/time.h>
 #include <linux/jiffies.h>
 #include <linux/interrupt.h>
 #include <linux/swap.h>
 #include <linux/sched.h>
 #include <linux/init.h>
 #include <linux/threads.h>
 #include <linux/cpufreq.h>
 #include <asm/types.h>
 #include <asm/signal.h>
 #include <asm/io.h>
 #include <asm/delay.h>
 #include <asm/rtc.h>
 #include <asm/irq.h>
 #include <asm/irq_regs.h>

 #include <hwregs/reg_map.h>
 #include <hwregs/reg_rdwr.h>
 #include <hwregs/timer_defs.h>
 #include <hwregs/intr_vect_defs.h>
 #ifdef CONFIG_CRIS_MACH_ARTPEC3
 #include <hwregs/clkgen_defs.h>
 #endif

 /* Watchdog defines */
 #define ETRAX_WD_KEY_MASK	0x7F /* key is 7 bit */
 #define ETRAX_WD_HZ		763 /* watchdog counts at 763 Hz */
 /* Number of 763 counts before watchdog bites */
 #define ETRAX_WD_CNT		((2*ETRAX_WD_HZ)/HZ + 1)

 unsigned long timer_regs[NR_CPUS] =
 {
 	regi_timer0,
 #ifdef CONFIG_SMP
 	regi_timer2
 #endif
 };

 extern void update_xtime_from_cmos(void);
 extern int set_rtc_mmss(unsigned long nowtime);
 extern int have_rtc;

 #ifdef CONFIG_CPU_FREQ
 static int
 cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
 			void *data);

 static struct notifier_block cris_time_freq_notifier_block = {
 	.notifier_call = cris_time_freq_notifier,
 };
 #endif

 unsigned long get_ns_in_jiffie(void)
 {
 	reg_timer_r_tmr0_data data;
 	unsigned long ns;

 	data = REG_RD(timer, regi_timer0, r_tmr0_data);
 	ns = (TIMER0_DIV - data) * 10;
 	return ns;
 }

 unsigned long do_slow_gettimeoffset(void)
 {
 	unsigned long count;
 	unsigned long usec_count = 0;

 	/* For the first call after boot */
 	static unsigned long count_p = TIMER0_DIV;
 	static unsigned long jiffies_p = 0;

 	/* Cache volatile jiffies temporarily; we have IRQs turned off. */
 	unsigned long jiffies_t;

 	/* The timer interrupt comes from Etrax timer 0. In order to get
 	 * better precision, we check the current value. It might have
 	 * underflowed already though. */
 	count = REG_RD(timer, regi_timer0, r_tmr0_data);
 	jiffies_t = jiffies;

 	/* Avoiding timer inconsistencies (they are rare, but they happen)
 	 * There is one problem that must be avoided here:
 	 *	1. the timer counter underflows
 	 */
 	if( jiffies_t == jiffies_p ) {
 		if( count > count_p ) {
 			/* Timer wrapped, use new count and prescale.
 			 * Increase the time corresponding to one jiffy.
 			 */
 			usec_count = 1000000/HZ;
 		}
 	} else
 		jiffies_p = jiffies_t;
         count_p = count;
 	/* Convert timer value to usec */
 	/* 100 MHz timer, divide by 100 to get usec */
 	usec_count +=  (TIMER0_DIV - count) / 100;
 	return usec_count;
 }

 /* From timer MDS describing the hardware watchdog:
  * 4.3.1 Watchdog Operation
  * The watchdog timer is an 8-bit timer with a configurable start value.
  * Once started the watchdog counts downwards with a frequency of 763 Hz
  * (100/131072 MHz). When the watchdog counts down to 1, it generates an
  * NMI (Non Maskable Interrupt), and when it counts down to 0, it resets the
  * chip.
  */
 /* This gives us 1.3 ms to do something useful when the NMI comes */

 /* Right now, starting the watchdog is the same as resetting it */
 #define start_watchdog reset_watchdog

 #if defined(CONFIG_ETRAX_WATCHDOG)
 static short int watchdog_key = 42;  /* arbitrary 7 bit number */
 #endif

 /* Number of pages to consider "out of memory". It is normal that the memory
  * is used though, so set this really low. */
 #define WATCHDOG_MIN_FREE_PAGES 8

 void
 reset_watchdog(void)
 {
 #if defined(CONFIG_ETRAX_WATCHDOG)
 	reg_timer_rw_wd_ctrl wd_ctrl = { 0 };

 	/* Only keep watchdog happy as long as we have memory left! */
 	if(nr_free_pages() > WATCHDOG_MIN_FREE_PAGES) {
 		/* Reset the watchdog with the inverse of the old key */
 		/* Invert key, which is 7 bits */
 		watchdog_key ^= ETRAX_WD_KEY_MASK;
 		wd_ctrl.cnt = ETRAX_WD_CNT;
 		wd_ctrl.cmd = regk_timer_start;
 		wd_ctrl.key = watchdog_key;
 		REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
 	}
 #endif
 }

 /* stop the watchdog - we still need the correct key */

 void
 stop_watchdog(void)
 {
 #if defined(CONFIG_ETRAX_WATCHDOG)
 	reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
 	watchdog_key ^= ETRAX_WD_KEY_MASK; /* invert key, which is 7 bits */
 	wd_ctrl.cnt = ETRAX_WD_CNT;
 	wd_ctrl.cmd = regk_timer_stop;
 	wd_ctrl.key = watchdog_key;
 	REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
 #endif
 }

 extern void show_registers(struct pt_regs *regs);

 void
 handle_watchdog_bite(struct pt_regs* regs)
 {
 #if defined(CONFIG_ETRAX_WATCHDOG)
 	extern int cause_of_death;

 	oops_in_progress = 1;
 	printk(KERN_WARNING "Watchdog bite\n");

 	/* Check if forced restart or unexpected watchdog */
 	if (cause_of_death == 0xbedead) {
 #ifdef CONFIG_CRIS_MACH_ARTPEC3
 		/* There is a bug in Artpec-3 (voodoo TR 78) that requires
 		 * us to go to lower frequency for the reset to be reliable
 		 */
 		reg_clkgen_rw_clk_ctrl ctrl =
 			REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
 		ctrl.pll = 0;
 		REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, ctrl);
 #endif
 		while(1);
 	}

 	/* Unexpected watchdog, stop the watchdog and dump registers. */
 	stop_watchdog();
 	printk(KERN_WARNING "Oops: bitten by watchdog\n");
 	show_registers(regs);
 	oops_in_progress = 0;
 #ifndef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
 	reset_watchdog();
 #endif
 	while(1) /* nothing */;
 #endif
 }

 /* Last time the cmos clock got updated. */
 static long last_rtc_update = 0;

 /*
  * timer_interrupt() needs to keep up the real-time clock,
  * as well as call the "do_timer()" routine every clocktick.
  */
 extern void cris_do_profile(struct pt_regs *regs);

 static inline irqreturn_t
 timer_interrupt(int irq, void *dev_id)
 {
 	struct pt_regs *regs = get_irq_regs();
 	int cpu = smp_processor_id();
 	reg_timer_r_masked_intr masked_intr;
 	reg_timer_rw_ack_intr ack_intr = { 0 };

 	/* Check if the timer interrupt is for us (a tmr0 int) */
 	masked_intr = REG_RD(timer, timer_regs[cpu], r_masked_intr);
 	if (!masked_intr.tmr0)
 		return IRQ_NONE;

 	/* Acknowledge the timer irq. */
 	ack_intr.tmr0 = 1;
 	REG_WR(timer, timer_regs[cpu], rw_ack_intr, ack_intr);

 	/* Reset watchdog otherwise it resets us! */
 	reset_watchdog();

         /* Update statistics. */
 	update_process_times(user_mode(regs));

 	cris_do_profile(regs); /* Save profiling information */

 	/* The master CPU is responsible for the time keeping. */
 	if (cpu != 0)
 		return IRQ_HANDLED;

 	/* Call the real timer interrupt handler */
 	do_timer(1);

 	/*
 	 * If we have an externally synchronized Linux clock, then update
 	 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
 	 * called as close as possible to 500 ms before the new second starts.
 	 *
 	 * The division here is not time critical since it will run once in
 	 * 11 minutes
 	 */
 	if ((time_status & STA_UNSYNC) == 0 &&
 	    xtime.tv_sec > last_rtc_update + 660 &&
 	    (xtime.tv_nsec / 1000) >= 500000 - (tick_nsec / 1000) / 2 &&
 	    (xtime.tv_nsec / 1000) <= 500000 + (tick_nsec / 1000) / 2) {
 		if (set_rtc_mmss(xtime.tv_sec) == 0)
 			last_rtc_update = xtime.tv_sec;
 		else
 			/* Do it again in 60 s */
 			last_rtc_update = xtime.tv_sec - 600;
 	}
         return IRQ_HANDLED;
 }

 /* Timer is IRQF_SHARED so drivers can add stuff to the timer irq chain.
  * It needs to be IRQF_DISABLED to make the jiffies update work properly.
  */
 static struct irqaction irq_timer = {
 	.handler = timer_interrupt,
 	.flags = IRQF_SHARED | IRQF_DISABLED,
 	.name = "timer"
 };

 void __init
 cris_timer_init(void)
 {
 	int cpu = smp_processor_id();
 	reg_timer_rw_tmr0_ctrl tmr0_ctrl = { 0 };
 	reg_timer_rw_tmr0_div tmr0_div = TIMER0_DIV;
 	reg_timer_rw_intr_mask timer_intr_mask;

 	/* Setup the etrax timers.
 	 * Base frequency is 100MHz, divider 1000000 -> 100 HZ
 	 * We use timer0, so timer1 is free.
 	 * The trig timer is used by the fasttimer API if enabled.
 	 */

 	tmr0_ctrl.op = regk_timer_ld;
 	tmr0_ctrl.freq = regk_timer_f100;
 	REG_WR(timer, timer_regs[cpu], rw_tmr0_div, tmr0_div);
 	REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Load */
 	tmr0_ctrl.op = regk_timer_run;
 	REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Start */

 	/* Enable the timer irq. */
 	timer_intr_mask = REG_RD(timer, timer_regs[cpu], rw_intr_mask);
 	timer_intr_mask.tmr0 = 1;
 	REG_WR(timer, timer_regs[cpu], rw_intr_mask, timer_intr_mask);
 }

 void __init
 time_init(void)
 {
 	reg_intr_vect_rw_mask intr_mask;

 	/* Probe for the RTC and read it if it exists.
 	 * Before the RTC can be probed the loops_per_usec variable needs
 	 * to be initialized to make usleep work. A better value for
 	 * loops_per_usec is calculated by the kernel later once the
 	 * clock has started.
 	 */
 	loops_per_usec = 50;

 	if(RTC_INIT() < 0) {
 		/* No RTC, start at 1980 */
 		xtime.tv_sec = 0;
 		xtime.tv_nsec = 0;
 		have_rtc = 0;
 	} else {
 		/* Get the current time */
 		have_rtc = 1;
 		update_xtime_from_cmos();
 	}

 	/*
 	 * Initialize wall_to_monotonic such that adding it to
 	 * xtime will yield zero, the tv_nsec field must be normalized
 	 * (i.e., 0 <= nsec < NSEC_PER_SEC).
 	 */
 	set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec);

 	/* Start CPU local timer. */
 	cris_timer_init();

 	/* Enable the timer irq in global config. */
 	intr_mask = REG_RD_VECT(intr_vect, regi_irq, rw_mask, 1);
 	intr_mask.timer0 = 1;
 	REG_WR_VECT(intr_vect, regi_irq, rw_mask, 1, intr_mask);

 	/* Now actually register the timer irq handler that calls
 	 * timer_interrupt(). */
 	setup_irq(TIMER0_INTR_VECT, &irq_timer);

 	/* Enable watchdog if we should use one. */

 #if defined(CONFIG_ETRAX_WATCHDOG)
 	printk(KERN_INFO "Enabling watchdog...\n");
 	start_watchdog();

 	/* If we use the hardware watchdog, we want to trap it as an NMI
 	 * and dump registers before it resets us.  For this to happen, we
 	 * must set the "m" NMI enable flag (which once set, is unset only
 	 * when an NMI is taken). */
 	{
 		unsigned long flags;
 		local_save_flags(flags);
 		flags |= (1<<30); /* NMI M flag is at bit 30 */
 		local_irq_restore(flags);
 	}
 #endif

 #ifdef CONFIG_CPU_FREQ
 	cpufreq_register_notifier(&cris_time_freq_notifier_block,
 		CPUFREQ_TRANSITION_NOTIFIER);
 #endif
 }

 #ifdef CONFIG_CPU_FREQ
 static int
 cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
 			void *data)
 {
 	struct cpufreq_freqs *freqs = data;
 	if (val == CPUFREQ_POSTCHANGE) {
 		reg_timer_r_tmr0_data data;
 		reg_timer_rw_tmr0_div div = (freqs->new * 500) / HZ;
 		do {
 			data = REG_RD(timer, timer_regs[freqs->cpu],
 				r_tmr0_data);
 		} while (data > 20);
 		REG_WR(timer, timer_regs[freqs->cpu], rw_tmr0_div, div);
 	}
 	return 0;
 }
 #endif
	/*
	* linux/arch/cris/arch-v32/kernel/time.c
	*
	* Copyright (C) 2003-2007 Axis Communications AB
	*
	*/

	#include <linux/timex.h>
	#include <linux/time.h>
	#include <linux/jiffies.h>
	#include <linux/interrupt.h>
	#include <linux/swap.h>
	#include <linux/sched.h>
	#include <linux/init.h>
	#include <linux/threads.h>
	#include <linux/cpufreq.h>
	#include <asm/types.h>
	#include <asm/signal.h>
	#include <asm/io.h>
	#include <asm/delay.h>
	#include <asm/rtc.h>
	#include <asm/irq.h>
	#include <asm/irq_regs.h>

	#include <hwregs/reg_map.h>
	#include <hwregs/reg_rdwr.h>
	#include <hwregs/timer_defs.h>
	#include <hwregs/intr_vect_defs.h>
	#ifdef CONFIG_CRIS_MACH_ARTPEC3
	#include <hwregs/clkgen_defs.h>
	#endif

	/* Watchdog defines */
	#define ETRAX_WD_KEY_MASK 0x7F /* key is 7 bit */
	#define ETRAX_WD_HZ 763 /* watchdog counts at 763 Hz */
	/* Number of 763 counts before watchdog bites */
	#define ETRAX_WD_CNT ((2*ETRAX_WD_HZ)/HZ + 1)

	unsigned long timer_regs[NR_CPUS] =
	{
	regi_timer0,
	#ifdef CONFIG_SMP
	regi_timer2
	#endif
	};

	extern void update_xtime_from_cmos(void);
	extern int set_rtc_mmss(unsigned long nowtime);
	extern int have_rtc;

	#ifdef CONFIG_CPU_FREQ
	static int
	cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
	void *data);

	static struct notifier_block cris_time_freq_notifier_block = {
	.notifier_call = cris_time_freq_notifier,
	};
	#endif

	unsigned long get_ns_in_jiffie(void)
	{
	reg_timer_r_tmr0_data data;
	unsigned long ns;

	data = REG_RD(timer, regi_timer0, r_tmr0_data);
	ns = (TIMER0_DIV - data) * 10;
	return ns;
	}

	unsigned long do_slow_gettimeoffset(void)
	{
	unsigned long count;
	unsigned long usec_count = 0;

	/* For the first call after boot */
	static unsigned long count_p = TIMER0_DIV;
	static unsigned long jiffies_p = 0;

	/* Cache volatile jiffies temporarily; we have IRQs turned off. */
	unsigned long jiffies_t;

	/* The timer interrupt comes from Etrax timer 0. In order to get
	* better precision, we check the current value. It might have
	* underflowed already though. */
	count = REG_RD(timer, regi_timer0, r_tmr0_data);
	jiffies_t = jiffies;

	/* Avoiding timer inconsistencies (they are rare, but they happen)
	* There is one problem that must be avoided here:
	* 1. the timer counter underflows
	*/
	if( jiffies_t == jiffies_p ) {
	if( count > count_p ) {
	/* Timer wrapped, use new count and prescale.
	* Increase the time corresponding to one jiffy.
	*/
	usec_count = 1000000/HZ;
	}
	} else
	jiffies_p = jiffies_t;
	count_p = count;
	/* Convert timer value to usec */
	/* 100 MHz timer, divide by 100 to get usec */
	usec_count += (TIMER0_DIV - count) / 100;
	return usec_count;
	}

	/* From timer MDS describing the hardware watchdog:
	* 4.3.1 Watchdog Operation
	* The watchdog timer is an 8-bit timer with a configurable start value.
	* Once started the watchdog counts downwards with a frequency of 763 Hz
	* (100/131072 MHz). When the watchdog counts down to 1, it generates an
	* NMI (Non Maskable Interrupt), and when it counts down to 0, it resets the
	* chip.
	*/
	/* This gives us 1.3 ms to do something useful when the NMI comes */

	/* Right now, starting the watchdog is the same as resetting it */
	#define start_watchdog reset_watchdog

	#if defined(CONFIG_ETRAX_WATCHDOG)
	static short int watchdog_key = 42; /* arbitrary 7 bit number */
	#endif

	/* Number of pages to consider "out of memory". It is normal that the memory
	* is used though, so set this really low. */
	#define WATCHDOG_MIN_FREE_PAGES 8

	void
	reset_watchdog(void)
	{
	#if defined(CONFIG_ETRAX_WATCHDOG)
	reg_timer_rw_wd_ctrl wd_ctrl = { 0 };

	/* Only keep watchdog happy as long as we have memory left! */
	if(nr_free_pages() > WATCHDOG_MIN_FREE_PAGES) {
	/* Reset the watchdog with the inverse of the old key */
	/* Invert key, which is 7 bits */
	watchdog_key ^= ETRAX_WD_KEY_MASK;
	wd_ctrl.cnt = ETRAX_WD_CNT;
	wd_ctrl.cmd = regk_timer_start;
	wd_ctrl.key = watchdog_key;
	REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
	}
	#endif
	}

	/* stop the watchdog - we still need the correct key */

	void
	stop_watchdog(void)
	{
	#if defined(CONFIG_ETRAX_WATCHDOG)
	reg_timer_rw_wd_ctrl wd_ctrl = { 0 };
	watchdog_key ^= ETRAX_WD_KEY_MASK; /* invert key, which is 7 bits */
	wd_ctrl.cnt = ETRAX_WD_CNT;
	wd_ctrl.cmd = regk_timer_stop;
	wd_ctrl.key = watchdog_key;
	REG_WR(timer, regi_timer0, rw_wd_ctrl, wd_ctrl);
	#endif
	}

	extern void show_registers(struct pt_regs *regs);

	void
	handle_watchdog_bite(struct pt_regs* regs)
	{
	#if defined(CONFIG_ETRAX_WATCHDOG)
	extern int cause_of_death;

	oops_in_progress = 1;
	printk(KERN_WARNING "Watchdog bite\n");

	/* Check if forced restart or unexpected watchdog */
	if (cause_of_death == 0xbedead) {
	#ifdef CONFIG_CRIS_MACH_ARTPEC3
	/* There is a bug in Artpec-3 (voodoo TR 78) that requires
	* us to go to lower frequency for the reset to be reliable
	*/
	reg_clkgen_rw_clk_ctrl ctrl =
	REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
	ctrl.pll = 0;
	REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, ctrl);
	#endif
	while(1);
	}

	/* Unexpected watchdog, stop the watchdog and dump registers. */
	stop_watchdog();
	printk(KERN_WARNING "Oops: bitten by watchdog\n");
	show_registers(regs);
	oops_in_progress = 0;
	#ifndef CONFIG_ETRAX_WATCHDOG_NICE_DOGGY
	reset_watchdog();
	#endif
	while(1) /* nothing */;
	#endif
	}

	/* Last time the cmos clock got updated. */
	static long last_rtc_update = 0;

	/*
	* timer_interrupt() needs to keep up the real-time clock,
	* as well as call the "do_timer()" routine every clocktick.
	*/
	extern void cris_do_profile(struct pt_regs *regs);

	static inline irqreturn_t
	timer_interrupt(int irq, void *dev_id)
	{
	struct pt_regs *regs = get_irq_regs();
	int cpu = smp_processor_id();
	reg_timer_r_masked_intr masked_intr;
	reg_timer_rw_ack_intr ack_intr = { 0 };

	/* Check if the timer interrupt is for us (a tmr0 int) */
	masked_intr = REG_RD(timer, timer_regs[cpu], r_masked_intr);
	if (!masked_intr.tmr0)
	return IRQ_NONE;

	/* Acknowledge the timer irq. */
	ack_intr.tmr0 = 1;
	REG_WR(timer, timer_regs[cpu], rw_ack_intr, ack_intr);

	/* Reset watchdog otherwise it resets us! */
	reset_watchdog();

	/* Update statistics. */
	update_process_times(user_mode(regs));

	cris_do_profile(regs); /* Save profiling information */

	/* The master CPU is responsible for the time keeping. */
	if (cpu != 0)
	return IRQ_HANDLED;

	/* Call the real timer interrupt handler */
	do_timer(1);

	/*
	* If we have an externally synchronized Linux clock, then update
	* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
	* called as close as possible to 500 ms before the new second starts.
	*
	* The division here is not time critical since it will run once in
	* 11 minutes
	*/
	if ((time_status & STA_UNSYNC) == 0 &&
	xtime.tv_sec > last_rtc_update + 660 &&
	(xtime.tv_nsec / 1000) >= 500000 - (tick_nsec / 1000) / 2 &&
	(xtime.tv_nsec / 1000) <= 500000 + (tick_nsec / 1000) / 2) {
	if (set_rtc_mmss(xtime.tv_sec) == 0)
	last_rtc_update = xtime.tv_sec;
	else
	/* Do it again in 60 s */
	last_rtc_update = xtime.tv_sec - 600;
	}
	return IRQ_HANDLED;
	}

	/* Timer is IRQF_SHARED so drivers can add stuff to the timer irq chain.
	* It needs to be IRQF_DISABLED to make the jiffies update work properly.
	*/
	static struct irqaction irq_timer = {
	.handler = timer_interrupt,
	.flags = IRQF_SHARED \| IRQF_DISABLED,
	.name = "timer"
	};

	void __init
	cris_timer_init(void)
	{
	int cpu = smp_processor_id();
	reg_timer_rw_tmr0_ctrl tmr0_ctrl = { 0 };
	reg_timer_rw_tmr0_div tmr0_div = TIMER0_DIV;
	reg_timer_rw_intr_mask timer_intr_mask;

	/* Setup the etrax timers.
	* Base frequency is 100MHz, divider 1000000 -> 100 HZ
	* We use timer0, so timer1 is free.
	* The trig timer is used by the fasttimer API if enabled.
	*/

	tmr0_ctrl.op = regk_timer_ld;
	tmr0_ctrl.freq = regk_timer_f100;
	REG_WR(timer, timer_regs[cpu], rw_tmr0_div, tmr0_div);
	REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Load */
	tmr0_ctrl.op = regk_timer_run;
	REG_WR(timer, timer_regs[cpu], rw_tmr0_ctrl, tmr0_ctrl); /* Start */

	/* Enable the timer irq. */
	timer_intr_mask = REG_RD(timer, timer_regs[cpu], rw_intr_mask);
	timer_intr_mask.tmr0 = 1;
	REG_WR(timer, timer_regs[cpu], rw_intr_mask, timer_intr_mask);
	}

	void __init
	time_init(void)
	{
	reg_intr_vect_rw_mask intr_mask;

	/* Probe for the RTC and read it if it exists.
	* Before the RTC can be probed the loops_per_usec variable needs
	* to be initialized to make usleep work. A better value for
	* loops_per_usec is calculated by the kernel later once the
	* clock has started.
	*/
	loops_per_usec = 50;

	if(RTC_INIT() < 0) {
	/* No RTC, start at 1980 */
	xtime.tv_sec = 0;
	xtime.tv_nsec = 0;
	have_rtc = 0;
	} else {
	/* Get the current time */
	have_rtc = 1;
	update_xtime_from_cmos();
	}

	/*
	* Initialize wall_to_monotonic such that adding it to
	* xtime will yield zero, the tv_nsec field must be normalized
	* (i.e., 0 <= nsec < NSEC_PER_SEC).
	*/
	set_normalized_timespec(&wall_to_monotonic, -xtime.tv_sec, -xtime.tv_nsec);

	/* Start CPU local timer. */
	cris_timer_init();

	/* Enable the timer irq in global config. */
	intr_mask = REG_RD_VECT(intr_vect, regi_irq, rw_mask, 1);
	intr_mask.timer0 = 1;
	REG_WR_VECT(intr_vect, regi_irq, rw_mask, 1, intr_mask);

	/* Now actually register the timer irq handler that calls
	* timer_interrupt(). */
	setup_irq(TIMER0_INTR_VECT, &irq_timer);

	/* Enable watchdog if we should use one. */

	#if defined(CONFIG_ETRAX_WATCHDOG)
	printk(KERN_INFO "Enabling watchdog...\n");
	start_watchdog();

	/* If we use the hardware watchdog, we want to trap it as an NMI
	* and dump registers before it resets us. For this to happen, we
	* must set the "m" NMI enable flag (which once set, is unset only
	* when an NMI is taken). */
	{
	unsigned long flags;
	local_save_flags(flags);
	flags \|= (1<<30); /* NMI M flag is at bit 30 */
	local_irq_restore(flags);
	}
	#endif

	#ifdef CONFIG_CPU_FREQ
	cpufreq_register_notifier(&cris_time_freq_notifier_block,
	CPUFREQ_TRANSITION_NOTIFIER);
	#endif
	}

	#ifdef CONFIG_CPU_FREQ
	static int
	cris_time_freq_notifier(struct notifier_block *nb, unsigned long val,
	void *data)
	{
	struct cpufreq_freqs *freqs = data;
	if (val == CPUFREQ_POSTCHANGE) {
	reg_timer_r_tmr0_data data;
	reg_timer_rw_tmr0_div div = (freqs->new * 500) / HZ;
	do {
	data = REG_RD(timer, timer_regs[freqs->cpu],
	r_tmr0_data);
	} while (data > 20);
	REG_WR(timer, timer_regs[freqs->cpu], rw_tmr0_div, div);
	}
	return 0;
	}
	#endif