Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 591 insertions, 0 deletions

diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c
new file mode 100644
index 00000000000..8226c5cd788
--- /dev/null
+++ b/arch/alpha/kernel/time.c
@@ -0,0 +1,591 @@
+/*
+ *  linux/arch/alpha/kernel/time.c
+ *
+ *  Copyright (C) 1991, 1992, 1995, 1999, 2000  Linus Torvalds
+ *
+ * This file contains the PC-specific time handling details:
+ * reading the RTC at bootup, etc..
+ * 1994-07-02    Alan Modra
+ *	fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
+ * 1995-03-26    Markus Kuhn
+ *      fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
+ *      precision CMOS clock update
+ * 1997-09-10	Updated NTP code according to technical memorandum Jan '96
+ *		"A Kernel Model for Precision Timekeeping" by Dave Mills
+ * 1997-01-09    Adrian Sun
+ *      use interval timer if CONFIG_RTC=y
+ * 1997-10-29    John Bowman (bowman@math.ualberta.ca)
+ *      fixed tick loss calculation in timer_interrupt
+ *      (round system clock to nearest tick instead of truncating)
+ *      fixed algorithm in time_init for getting time from CMOS clock
+ * 1999-04-16	Thorsten Kranzkowski (dl8bcu@gmx.net)
+ *	fixed algorithm in do_gettimeofday() for calculating the precise time
+ *	from processor cycle counter (now taking lost_ticks into account)
+ * 2000-08-13	Jan-Benedict Glaw <jbglaw@lug-owl.de>
+ * 	Fixed time_init to be aware of epoches != 1900. This prevents
+ * 	booting up in 2048 for me;) Code is stolen from rtc.c.
+ * 2003-06-03	R. Scott Bailey <scott.bailey@eds.com>
+ *	Tighten sanity in time_init from 1% (10,000 PPM) to 250 PPM
+ */
+#include <linux/config.h>
+#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/delay.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <linux/bcd.h>
+#include <linux/profile.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/hwrpb.h>
+#include <asm/8253pit.h>
+
+#include <linux/mc146818rtc.h>
+#include <linux/time.h>
+#include <linux/timex.h>
+
+#include "proto.h"
+#include "irq_impl.h"
+
+u64 jiffies_64 = INITIAL_JIFFIES;
+
+EXPORT_SYMBOL(jiffies_64);
+
+extern unsigned long wall_jiffies;	/* kernel/timer.c */
+
+static int set_rtc_mmss(unsigned long);
+
+DEFINE_SPINLOCK(rtc_lock);
+
+#define TICK_SIZE (tick_nsec / 1000)
+
+/*
+ * Shift amount by which scaled_ticks_per_cycle is scaled.  Shifting
+ * by 48 gives us 16 bits for HZ while keeping the accuracy good even
+ * for large CPU clock rates.
+ */
+#define FIX_SHIFT	48
+
+/* lump static variables together for more efficient access: */
+static struct {
+	/* cycle counter last time it got invoked */
+	__u32 last_time;
+	/* ticks/cycle * 2^48 */
+	unsigned long scaled_ticks_per_cycle;
+	/* last time the CMOS clock got updated */
+	time_t last_rtc_update;
+	/* partial unused tick */
+	unsigned long partial_tick;
+} state;
+
+unsigned long est_cycle_freq;
+
+
+static inline __u32 rpcc(void)
+{
+    __u32 result;
+    asm volatile ("rpcc %0" : "=r"(result));
+    return result;
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ *
+ * Copied from ARM code for expediency... ;-}
+ */
+unsigned long long sched_clock(void)
+{
+        return (unsigned long long)jiffies * (1000000000 / HZ);
+}
+
+
+/*
+ * timer_interrupt() needs to keep up the real-time clock,
+ * as well as call the "do_timer()" routine every clocktick
+ */
+irqreturn_t timer_interrupt(int irq, void *dev, struct pt_regs * regs)
+{
+	unsigned long delta;
+	__u32 now;
+	long nticks;
+
+#ifndef CONFIG_SMP
+	/* Not SMP, do kernel PC profiling here.  */
+	profile_tick(CPU_PROFILING, regs);
+#endif
+
+	write_seqlock(&xtime_lock);
+
+	/*
+	 * Calculate how many ticks have passed since the last update,
+	 * including any previous partial leftover.  Save any resulting
+	 * fraction for the next pass.
+	 */
+	now = rpcc();
+	delta = now - state.last_time;
+	state.last_time = now;
+	delta = delta * state.scaled_ticks_per_cycle + state.partial_tick;
+	state.partial_tick = delta & ((1UL << FIX_SHIFT) - 1); 
+	nticks = delta >> FIX_SHIFT;
+
+	while (nticks > 0) {
+		do_timer(regs);
+#ifndef CONFIG_SMP
+		update_process_times(user_mode(regs));
+#endif
+		nticks--;
+	}
+
+	/*
+	 * 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.
+	 */
+	if ((time_status & STA_UNSYNC) == 0
+	    && xtime.tv_sec > state.last_rtc_update + 660
+	    && xtime.tv_nsec >= 500000 - ((unsigned) TICK_SIZE) / 2
+	    && xtime.tv_nsec <= 500000 + ((unsigned) TICK_SIZE) / 2) {
+		int tmp = set_rtc_mmss(xtime.tv_sec);
+		state.last_rtc_update = xtime.tv_sec - (tmp ? 600 : 0);
+	}
+
+	write_sequnlock(&xtime_lock);
+	return IRQ_HANDLED;
+}
+
+void
+common_init_rtc(void)
+{
+	unsigned char x;
+
+	/* Reset periodic interrupt frequency.  */
+	x = CMOS_READ(RTC_FREQ_SELECT) & 0x3f;
+        /* Test includes known working values on various platforms
+           where 0x26 is wrong; we refuse to change those. */
+	if (x != 0x26 && x != 0x25 && x != 0x19 && x != 0x06) {
+		printk("Setting RTC_FREQ to 1024 Hz (%x)\n", x);
+		CMOS_WRITE(0x26, RTC_FREQ_SELECT);
+	}
+
+	/* Turn on periodic interrupts.  */
+	x = CMOS_READ(RTC_CONTROL);
+	if (!(x & RTC_PIE)) {
+		printk("Turning on RTC interrupts.\n");
+		x |= RTC_PIE;
+		x &= ~(RTC_AIE | RTC_UIE);
+		CMOS_WRITE(x, RTC_CONTROL);
+	}
+	(void) CMOS_READ(RTC_INTR_FLAGS);
+
+	outb(0x36, 0x43);	/* pit counter 0: system timer */
+	outb(0x00, 0x40);
+	outb(0x00, 0x40);
+
+	outb(0xb6, 0x43);	/* pit counter 2: speaker */
+	outb(0x31, 0x42);
+	outb(0x13, 0x42);
+
+	init_rtc_irq();
+}
+
+
+/* Validate a computed cycle counter result against the known bounds for
+   the given processor core.  There's too much brokenness in the way of
+   timing hardware for any one method to work everywhere.  :-(
+
+   Return 0 if the result cannot be trusted, otherwise return the argument.  */
+
+static unsigned long __init
+validate_cc_value(unsigned long cc)
+{
+	static struct bounds {
+		unsigned int min, max;
+	} cpu_hz[] __initdata = {
+		[EV3_CPU]    = {   50000000,  200000000 },	/* guess */
+		[EV4_CPU]    = {  100000000,  300000000 },
+		[LCA4_CPU]   = {  100000000,  300000000 },	/* guess */
+		[EV45_CPU]   = {  200000000,  300000000 },
+		[EV5_CPU]    = {  250000000,  433000000 },
+		[EV56_CPU]   = {  333000000,  667000000 },
+		[PCA56_CPU]  = {  400000000,  600000000 },	/* guess */
+		[PCA57_CPU]  = {  500000000,  600000000 },	/* guess */
+		[EV6_CPU]    = {  466000000,  600000000 },
+		[EV67_CPU]   = {  600000000,  750000000 },
+		[EV68AL_CPU] = {  750000000,  940000000 },
+		[EV68CB_CPU] = { 1000000000, 1333333333 },
+		/* None of the following are shipping as of 2001-11-01.  */
+		[EV68CX_CPU] = { 1000000000, 1700000000 },	/* guess */
+		[EV69_CPU]   = { 1000000000, 1700000000 },	/* guess */
+		[EV7_CPU]    = {  800000000, 1400000000 },	/* guess */
+		[EV79_CPU]   = { 1000000000, 2000000000 },	/* guess */
+	};
+
+	/* Allow for some drift in the crystal.  10MHz is more than enough.  */
+	const unsigned int deviation = 10000000;
+
+	struct percpu_struct *cpu;
+	unsigned int index;
+
+	cpu = (struct percpu_struct *)((char*)hwrpb + hwrpb->processor_offset);
+	index = cpu->type & 0xffffffff;
+
+	/* If index out of bounds, no way to validate.  */
+	if (index >= sizeof(cpu_hz)/sizeof(cpu_hz[0]))
+		return cc;
+
+	/* If index contains no data, no way to validate.  */
+	if (cpu_hz[index].max == 0)
+		return cc;
+
+	if (cc < cpu_hz[index].min - deviation
+	    || cc > cpu_hz[index].max + deviation)
+		return 0;
+
+	return cc;
+}
+
+
+/*
+ * Calibrate CPU clock using legacy 8254 timer/counter. Stolen from
+ * arch/i386/time.c.
+ */
+
+#define CALIBRATE_LATCH	0xffff
+#define TIMEOUT_COUNT	0x100000
+
+static unsigned long __init
+calibrate_cc_with_pit(void)
+{
+	int cc, count = 0;
+
+	/* Set the Gate high, disable speaker */
+	outb((inb(0x61) & ~0x02) | 0x01, 0x61);
+
+	/*
+	 * Now let's take care of CTC channel 2
+	 *
+	 * Set the Gate high, program CTC channel 2 for mode 0,
+	 * (interrupt on terminal count mode), binary count,
+	 * load 5 * LATCH count, (LSB and MSB) to begin countdown.
+	 */
+	outb(0xb0, 0x43);		/* binary, mode 0, LSB/MSB, Ch 2 */
+	outb(CALIBRATE_LATCH & 0xff, 0x42);	/* LSB of count */
+	outb(CALIBRATE_LATCH >> 8, 0x42);	/* MSB of count */
+
+	cc = rpcc();
+	do {
+		count++;
+	} while ((inb(0x61) & 0x20) == 0 && count < TIMEOUT_COUNT);
+	cc = rpcc() - cc;
+
+	/* Error: ECTCNEVERSET or ECPUTOOFAST.  */
+	if (count <= 1 || count == TIMEOUT_COUNT)
+		return 0;
+
+	return ((long)cc * PIT_TICK_RATE) / (CALIBRATE_LATCH + 1);
+}
+
+/* The Linux interpretation of the CMOS clock register contents:
+   When the Update-In-Progress (UIP) flag goes from 1 to 0, the
+   RTC registers show the second which has precisely just started.
+   Let's hope other operating systems interpret the RTC the same way.  */
+
+static unsigned long __init
+rpcc_after_update_in_progress(void)
+{
+	do { } while (!(CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP));
+	do { } while (CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP);
+
+	return rpcc();
+}
+
+void __init
+time_init(void)
+{
+	unsigned int year, mon, day, hour, min, sec, cc1, cc2, epoch;
+	unsigned long cycle_freq, tolerance;
+	long diff;
+
+	/* Calibrate CPU clock -- attempt #1.  */
+	if (!est_cycle_freq)
+		est_cycle_freq = validate_cc_value(calibrate_cc_with_pit());
+
+	cc1 = rpcc_after_update_in_progress();
+
+	/* Calibrate CPU clock -- attempt #2.  */
+	if (!est_cycle_freq) {
+		cc2 = rpcc_after_update_in_progress();
+		est_cycle_freq = validate_cc_value(cc2 - cc1);
+		cc1 = cc2;
+	}
+
+	cycle_freq = hwrpb->cycle_freq;
+	if (est_cycle_freq) {
+		/* If the given value is within 250 PPM of what we calculated,
+		   accept it.  Otherwise, use what we found.  */
+		tolerance = cycle_freq / 4000;
+		diff = cycle_freq - est_cycle_freq;
+		if (diff < 0)
+			diff = -diff;
+		if ((unsigned long)diff > tolerance) {
+			cycle_freq = est_cycle_freq;
+			printk("HWRPB cycle frequency bogus.  "
+			       "Estimated %lu Hz\n", cycle_freq);
+		} else {
+			est_cycle_freq = 0;
+		}
+	} else if (! validate_cc_value (cycle_freq)) {
+		printk("HWRPB cycle frequency bogus, "
+		       "and unable to estimate a proper value!\n");
+	}
+
+	/* From John Bowman <bowman@math.ualberta.ca>: allow the values
+	   to settle, as the Update-In-Progress bit going low isn't good
+	   enough on some hardware.  2ms is our guess; we haven't found 
+	   bogomips yet, but this is close on a 500Mhz box.  */
+	__delay(1000000);
+
+	sec = CMOS_READ(RTC_SECONDS);
+	min = CMOS_READ(RTC_MINUTES);
+	hour = CMOS_READ(RTC_HOURS);
+	day = CMOS_READ(RTC_DAY_OF_MONTH);
+	mon = CMOS_READ(RTC_MONTH);
+	year = CMOS_READ(RTC_YEAR);
+
+	if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+		BCD_TO_BIN(sec);
+		BCD_TO_BIN(min);
+		BCD_TO_BIN(hour);
+		BCD_TO_BIN(day);
+		BCD_TO_BIN(mon);
+		BCD_TO_BIN(year);
+	}
+
+	/* PC-like is standard; used for year >= 70 */
+	epoch = 1900;
+	if (year < 20)
+		epoch = 2000;
+	else if (year >= 20 && year < 48)
+		/* NT epoch */
+		epoch = 1980;
+	else if (year >= 48 && year < 70)
+		/* Digital UNIX epoch */
+		epoch = 1952;
+
+	printk(KERN_INFO "Using epoch = %d\n", epoch);
+
+	if ((year += epoch) < 1970)
+		year += 100;
+
+	xtime.tv_sec = mktime(year, mon, day, hour, min, sec);
+	xtime.tv_nsec = 0;
+
+        wall_to_monotonic.tv_sec -= xtime.tv_sec;
+        wall_to_monotonic.tv_nsec = 0;
+
+	if (HZ > (1<<16)) {
+		extern void __you_loose (void);
+		__you_loose();
+	}
+
+	state.last_time = cc1;
+	state.scaled_ticks_per_cycle
+		= ((unsigned long) HZ << FIX_SHIFT) / cycle_freq;
+	state.last_rtc_update = 0;
+	state.partial_tick = 0L;
+
+	/* Startup the timer source. */
+	alpha_mv.init_rtc();
+}
+
+/*
+ * Use the cycle counter to estimate an displacement from the last time
+ * tick.  Unfortunately the Alpha designers made only the low 32-bits of
+ * the cycle counter active, so we overflow on 8.2 seconds on a 500MHz
+ * part.  So we can't do the "find absolute time in terms of cycles" thing
+ * that the other ports do.
+ */
+void
+do_gettimeofday(struct timeval *tv)
+{
+	unsigned long flags;
+	unsigned long sec, usec, lost, seq;
+	unsigned long delta_cycles, delta_usec, partial_tick;
+
+	do {
+		seq = read_seqbegin_irqsave(&xtime_lock, flags);
+
+		delta_cycles = rpcc() - state.last_time;
+		sec = xtime.tv_sec;
+		usec = (xtime.tv_nsec / 1000);
+		partial_tick = state.partial_tick;
+		lost = jiffies - wall_jiffies;
+
+	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
+
+#ifdef CONFIG_SMP
+	/* Until and unless we figure out how to get cpu cycle counters
+	   in sync and keep them there, we can't use the rpcc tricks.  */
+	delta_usec = lost * (1000000 / HZ);
+#else
+	/*
+	 * usec = cycles * ticks_per_cycle * 2**48 * 1e6 / (2**48 * ticks)
+	 *	= cycles * (s_t_p_c) * 1e6 / (2**48 * ticks)
+	 *	= cycles * (s_t_p_c) * 15625 / (2**42 * ticks)
+	 *
+	 * which, given a 600MHz cycle and a 1024Hz tick, has a
+	 * dynamic range of about 1.7e17, which is less than the
+	 * 1.8e19 in an unsigned long, so we are safe from overflow.
+	 *
+	 * Round, but with .5 up always, since .5 to even is harder
+	 * with no clear gain.
+	 */
+
+	delta_usec = (delta_cycles * state.scaled_ticks_per_cycle 
+		      + partial_tick
+		      + (lost << FIX_SHIFT)) * 15625;
+	delta_usec = ((delta_usec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2;
+#endif
+
+	usec += delta_usec;
+	if (usec >= 1000000) {
+		sec += 1;
+		usec -= 1000000;
+	}
+
+	tv->tv_sec = sec;
+	tv->tv_usec = usec;
+}
+
+EXPORT_SYMBOL(do_gettimeofday);
+
+int
+do_settimeofday(struct timespec *tv)
+{
+	time_t wtm_sec, sec = tv->tv_sec;
+	long wtm_nsec, nsec = tv->tv_nsec;
+	unsigned long delta_nsec;
+
+	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
+		return -EINVAL;
+
+	write_seqlock_irq(&xtime_lock);
+
+	/* The offset that is added into time in do_gettimeofday above
+	   must be subtracted out here to keep a coherent view of the
+	   time.  Without this, a full-tick error is possible.  */
+
+#ifdef CONFIG_SMP
+	delta_nsec = (jiffies - wall_jiffies) * (NSEC_PER_SEC / HZ);
+#else
+	delta_nsec = rpcc() - state.last_time;
+	delta_nsec = (delta_nsec * state.scaled_ticks_per_cycle 
+		      + state.partial_tick
+		      + ((jiffies - wall_jiffies) << FIX_SHIFT)) * 15625;
+	delta_nsec = ((delta_nsec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2;
+	delta_nsec *= 1000;
+#endif
+
+	nsec -= delta_nsec;
+
+	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);
+
+	time_adjust = 0;		/* stop active adjtime() */
+	time_status |= STA_UNSYNC;
+	time_maxerror = NTP_PHASE_LIMIT;
+	time_esterror = NTP_PHASE_LIMIT;
+
+	write_sequnlock_irq(&xtime_lock);
+	clock_was_set();
+	return 0;
+}
+
+EXPORT_SYMBOL(do_settimeofday);
+
+
+/*
+ * In order to set the CMOS clock precisely, set_rtc_mmss has to be
+ * called 500 ms after the second nowtime has started, because when
+ * nowtime is written into the registers of the CMOS clock, it will
+ * jump to the next second precisely 500 ms later. Check the Motorola
+ * MC146818A or Dallas DS12887 data sheet for details.
+ *
+ * BUG: This routine does not handle hour overflow properly; it just
+ *      sets the minutes. Usually you won't notice until after reboot!
+ */
+
+
+static int
+set_rtc_mmss(unsigned long nowtime)
+{
+	int retval = 0;
+	int real_seconds, real_minutes, cmos_minutes;
+	unsigned char save_control, save_freq_select;
+
+	/* irq are locally disabled here */
+	spin_lock(&rtc_lock);
+	/* Tell the clock it's being set */
+	save_control = CMOS_READ(RTC_CONTROL);
+	CMOS_WRITE((save_control|RTC_SET), RTC_CONTROL);
+
+	/* Stop and reset prescaler */
+	save_freq_select = CMOS_READ(RTC_FREQ_SELECT);
+	CMOS_WRITE((save_freq_select|RTC_DIV_RESET2), RTC_FREQ_SELECT);
+
+	cmos_minutes = CMOS_READ(RTC_MINUTES);
+	if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD)
+		BCD_TO_BIN(cmos_minutes);
+
+	/*
+	 * since we're only adjusting minutes and seconds,
+	 * don't interfere with hour overflow. This avoids
+	 * messing with unknown time zones but requires your
+	 * RTC not to be off by more than 15 minutes
+	 */
+	real_seconds = nowtime % 60;
+	real_minutes = nowtime / 60;
+	if (((abs(real_minutes - cmos_minutes) + 15)/30) & 1) {
+		/* correct for half hour time zone */
+		real_minutes += 30;
+	}
+	real_minutes %= 60;
+
+	if (abs(real_minutes - cmos_minutes) < 30) {
+		if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
+			BIN_TO_BCD(real_seconds);
+			BIN_TO_BCD(real_minutes);
+		}
+		CMOS_WRITE(real_seconds,RTC_SECONDS);
+		CMOS_WRITE(real_minutes,RTC_MINUTES);
+	} else {
+		printk(KERN_WARNING
+		       "set_rtc_mmss: can't update from %d to %d\n",
+		       cmos_minutes, real_minutes);
+ 		retval = -1;
+	}
+
+	/* The following flags have to be released exactly in this order,
+	 * otherwise the DS12887 (popular MC146818A clone with integrated
+	 * battery and quartz) will not reset the oscillator and will not
+	 * update precisely 500 ms later. You won't find this mentioned in
+	 * the Dallas Semiconductor data sheets, but who believes data
+	 * sheets anyway ...                           -- Markus Kuhn
+	 */
+	CMOS_WRITE(save_control, RTC_CONTROL);
+	CMOS_WRITE(save_freq_select, RTC_FREQ_SELECT);
+	spin_unlock(&rtc_lock);
+
+	return retval;
+}