patch-2.4.19 linux-2.4.19/arch/mips64/kernel/time.c

Next file: linux-2.4.19/arch/mips64/kernel/traps.c
Previous file: linux-2.4.19/arch/mips64/kernel/syscall.c
Back to the patch index
Back to the overall index

diff -urN linux-2.4.18/arch/mips64/kernel/time.c linux-2.4.19/arch/mips64/kernel/time.c
@@ -0,0 +1,571 @@
+/*
+ * 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 <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))
+
+/*
+ * forward reference
+ */
+extern rwlock_t xtime_lock;
+extern volatile unsigned long wall_jiffies;
+
+/*
+ * 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;
+
+
+/*
+ * timeofday services, for syscalls.
+ */
+void do_gettimeofday(struct timeval *tv)
+{
+	unsigned long flags;
+
+	read_lock_irqsave (&xtime_lock, flags);
+	*tv = xtime;
+	tv->tv_usec += do_gettimeoffset();
+
+	/*
+	 * xtime is atomically updated in timer_bh. jiffies - wall_jiffies
+	 * is nonzero if the timer bottom half hasnt executed yet.
+	 */
+	if (jiffies - wall_jiffies)
+		tv->tv_usec += USECS_PER_JIFFY;
+
+	read_unlock_irqrestore (&xtime_lock, flags);
+
+	if (tv->tv_usec >= 1000000) {
+		tv->tv_usec -= 1000000;
+		tv->tv_sec++;
+	}
+}
+
+void do_settimeofday(struct timeval *tv)
+{
+	write_lock_irq (&xtime_lock);
+
+	/* This is revolting. We need to set the xtime.tv_usec
+	 * correctly. However, the value in this location is
+	 * is value at the last tick.
+	 * Discover what correction gettimeofday
+	 * would have done, and then undo it!
+	 */
+	tv->tv_usec -= do_gettimeoffset();
+
+	if (tv->tv_usec < 0) {
+		tv->tv_usec += 1000000;
+		tv->tv_sec--;
+	}
+	xtime = *tv;
+	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_32bit_cp0_register(CP0_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_32bit_cp0_register(CP0_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_32bit_cp0_register(CP0_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]);
+		}
+	}
+
+#if defined(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 (mips_cpu.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_32bit_cp0_register(CP0_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_32bit_cp0_register (CP0_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_usec >= 500000 - ((unsigned) tick) / 2 &&
+	    xtime.tv_usec <= 500000 + ((unsigned) tick) / 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(cpu, irq);
+	kstat.irqs[cpu][irq]++;
+
+	/* we keep interrupt disabled all the time */
+	timer_interrupt(irq, NULL, regs);
+	
+	irq_exit(cpu, irq);
+
+	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(cpu, irq);
+	kstat.irqs[cpu][irq]++;
+
+	/* we keep interrupt disabled all the time */
+	local_timer_interrupt(irq, NULL, regs);
+	
+	irq_exit(cpu, irq);
+
+	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_usec = 0;
+
+	/* choose appropriate gettimeoffset routine */
+	if (!(mips_cpu.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 ((mips_cpu.isa_level == MIPS_CPU_ISA_M32) ||
+		   (mips_cpu.isa_level == MIPS_CPU_ISA_I) ||
+		   (mips_cpu.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) {
+		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;
+	}
+
+	/* 
+	 * 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 */
+}
FUNET's LINUX-ADM group, linux-adm@nic.funet.fi
TCL-scripts by Sam Shen (who was at: slshen@lbl.gov)