powerpc: Merge time.c and asm/time.h.

We now use the merged time.c for both 32-bit and 64-bit compilation
with ARCH=powerpc, and for ARCH=ppc64, but not for ARCH=ppc32.
This removes setup_default_decr (folds its function into time_init)
and moves wakeup_decrementer into time.c.  This also makes an
asm-powerpc/rtc.h.

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 0 insertions, 879 deletions

diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c
deleted file mode 100644
index 7f63755eddfd..000000000000
--- a/arch/ppc64/kernel/time.c
+++ /dev/null
@@ -1,879 +0,0 @@
-/*
- * 
- * Common time routines among all ppc machines.
- *
- * Written by Cort Dougan (cort@cs.nmt.edu) to merge
- * Paul Mackerras' version and mine for PReP and Pmac.
- * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
- * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
- *
- * First round of bugfixes by Gabriel Paubert (paubert@iram.es)
- * to make clock more stable (2.4.0-test5). The only thing
- * that this code assumes is that the timebases have been synchronized
- * by firmware on SMP and are never stopped (never do sleep
- * on SMP then, nap and doze are OK).
- * 
- * Speeded up do_gettimeofday by getting rid of references to
- * xtime (which required locks for consistency). (mikejc@us.ibm.com)
- *
- * TODO (not necessarily in this file):
- * - improve precision and reproducibility of timebase frequency
- * measurement at boot time. (for iSeries, we calibrate the timebase
- * against the Titan chip's clock.)
- * - for astronomical applications: add a new function to get
- * non ambiguous timestamps even around leap seconds. This needs
- * a new timestamp format and a good name.
- *
- * 1997-09-10  Updated NTP code according to technical memorandum Jan '96
- *             "A Kernel Model for Precision Timekeeping" by Dave Mills
- *
- *      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/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/timex.h>
-#include <linux/kernel_stat.h>
-#include <linux/mc146818rtc.h>
-#include <linux/time.h>
-#include <linux/init.h>
-#include <linux/profile.h>
-#include <linux/cpu.h>
-#include <linux/security.h>
-
-#include <asm/io.h>
-#include <asm/processor.h>
-#include <asm/nvram.h>
-#include <asm/cache.h>
-#include <asm/machdep.h>
-#ifdef CONFIG_PPC_ISERIES
-#include <asm/iSeries/ItLpQueue.h>
-#include <asm/iSeries/HvCallXm.h>
-#endif
-#include <asm/uaccess.h>
-#include <asm/time.h>
-#include <asm/ppcdebug.h>
-#include <asm/prom.h>
-#include <asm/sections.h>
-#include <asm/systemcfg.h>
-#include <asm/firmware.h>
-
-u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
-
-EXPORT_SYMBOL(jiffies_64);
-
-/* keep track of when we need to update the rtc */
-time_t last_rtc_update;
-extern int piranha_simulator;
-#ifdef CONFIG_PPC_ISERIES
-unsigned long iSeries_recal_titan = 0;
-unsigned long iSeries_recal_tb = 0; 
-static unsigned long first_settimeofday = 1;
-#endif
-
-#define XSEC_PER_SEC (1024*1024)
-
-unsigned long tb_ticks_per_jiffy;
-unsigned long tb_ticks_per_usec = 100; /* sane default */
-EXPORT_SYMBOL(tb_ticks_per_usec);
-unsigned long tb_ticks_per_sec;
-unsigned long tb_to_xs;
-unsigned      tb_to_us;
-unsigned long processor_freq;
-DEFINE_SPINLOCK(rtc_lock);
-EXPORT_SYMBOL_GPL(rtc_lock);
-
-unsigned long tb_to_ns_scale;
-unsigned long tb_to_ns_shift;
-
-struct gettimeofday_struct do_gtod;
-
-extern unsigned long wall_jiffies;
-extern int smp_tb_synchronized;
-
-extern struct timezone sys_tz;
-
-void ppc_adjtimex(void);
-
-static unsigned adjusting_time = 0;
-
-unsigned long ppc_proc_freq;
-unsigned long ppc_tb_freq;
-
-static __inline__ void timer_check_rtc(void)
-{
-        /*
-         * update the rtc when needed, this should be performed on the
-         * right fraction of a second. Half or full second ?
-         * Full second works on mk48t59 clocks, others need testing.
-         * Note that this update is basically only used through 
-         * the adjtimex system calls. Setting the HW clock in
-         * any other way is a /dev/rtc and userland business.
-         * This is still wrong by -0.5/+1.5 jiffies because of the
-         * timer interrupt resolution and possible delay, but here we 
-         * hit a quantization limit which can only be solved by higher
-         * resolution timers and decoupling time management from timer
-         * interrupts. This is also wrong on the clocks
-         * which require being written at the half second boundary.
-         * We should have an rtc call that only sets the minutes and
-         * seconds like on Intel to avoid problems with non UTC clocks.
-         */
-        if (ntp_synced() &&
-             xtime.tv_sec - last_rtc_update >= 659 &&
-             abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ &&
-             jiffies - wall_jiffies == 1) {
-	    struct rtc_time tm;
-	    to_tm(xtime.tv_sec+1, &tm);
-	    tm.tm_year -= 1900;
-	    tm.tm_mon -= 1;
-            if (ppc_md.set_rtc_time(&tm) == 0)
-                last_rtc_update = xtime.tv_sec+1;
-            else
-                /* Try again one minute later */
-                last_rtc_update += 60;
-        }
-}
-
-/*
- * This version of gettimeofday has microsecond resolution.
- */
-static inline void __do_gettimeofday(struct timeval *tv, unsigned long tb_val)
-{
-	unsigned long sec, usec, tb_ticks;
-	unsigned long xsec, tb_xsec;
-	struct gettimeofday_vars * temp_varp;
-	unsigned long temp_tb_to_xs, temp_stamp_xsec;
-
-	/*
-	 * These calculations are faster (gets rid of divides)
-	 * if done in units of 1/2^20 rather than microseconds.
-	 * The conversion to microseconds at the end is done
-	 * without a divide (and in fact, without a multiply)
-	 */
-	temp_varp = do_gtod.varp;
-	tb_ticks = tb_val - temp_varp->tb_orig_stamp;
-	temp_tb_to_xs = temp_varp->tb_to_xs;
-	temp_stamp_xsec = temp_varp->stamp_xsec;
-	tb_xsec = mulhdu( tb_ticks, temp_tb_to_xs );
-	xsec = temp_stamp_xsec + tb_xsec;
-	sec = xsec / XSEC_PER_SEC;
-	xsec -= sec * XSEC_PER_SEC;
-	usec = (xsec * USEC_PER_SEC)/XSEC_PER_SEC;
-
-	tv->tv_sec = sec;
-	tv->tv_usec = usec;
-}
-
-void do_gettimeofday(struct timeval *tv)
-{
-	__do_gettimeofday(tv, get_tb());
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-
-/* Synchronize xtime with do_gettimeofday */ 
-
-static inline void timer_sync_xtime(unsigned long cur_tb)
-{
-	struct timeval my_tv;
-
-	__do_gettimeofday(&my_tv, cur_tb);
-
-	if (xtime.tv_sec <= my_tv.tv_sec) {
-		xtime.tv_sec = my_tv.tv_sec;
-		xtime.tv_nsec = my_tv.tv_usec * 1000;
-	}
-}
-
-/*
- * When the timebase - tb_orig_stamp gets too big, we do a manipulation
- * between tb_orig_stamp and stamp_xsec. The goal here is to keep the
- * difference tb - tb_orig_stamp small enough to always fit inside a
- * 32 bits number. This is a requirement of our fast 32 bits userland
- * implementation in the vdso. If we "miss" a call to this function
- * (interrupt latency, CPU locked in a spinlock, ...) and we end up
- * with a too big difference, then the vdso will fallback to calling
- * the syscall
- */
-static __inline__ void timer_recalc_offset(unsigned long cur_tb)
-{
-	struct gettimeofday_vars * temp_varp;
-	unsigned temp_idx;
-	unsigned long offset, new_stamp_xsec, new_tb_orig_stamp;
-
-	if (((cur_tb - do_gtod.varp->tb_orig_stamp) & 0x80000000u) == 0)
-		return;
-
-	temp_idx = (do_gtod.var_idx == 0);
-	temp_varp = &do_gtod.vars[temp_idx];
-
-	new_tb_orig_stamp = cur_tb;
-	offset = new_tb_orig_stamp - do_gtod.varp->tb_orig_stamp;
-	new_stamp_xsec = do_gtod.varp->stamp_xsec + mulhdu(offset, do_gtod.varp->tb_to_xs);
-
-	temp_varp->tb_to_xs = do_gtod.varp->tb_to_xs;
-	temp_varp->tb_orig_stamp = new_tb_orig_stamp;
-	temp_varp->stamp_xsec = new_stamp_xsec;
-	smp_mb();
-	do_gtod.varp = temp_varp;
-	do_gtod.var_idx = temp_idx;
-
-	++(systemcfg->tb_update_count);
-	smp_wmb();
-	systemcfg->tb_orig_stamp = new_tb_orig_stamp;
-	systemcfg->stamp_xsec = new_stamp_xsec;
-	smp_wmb();
-	++(systemcfg->tb_update_count);
-}
-
-#ifdef CONFIG_SMP
-unsigned long profile_pc(struct pt_regs *regs)
-{
-	unsigned long pc = instruction_pointer(regs);
-
-	if (in_lock_functions(pc))
-		return regs->link;
-
-	return pc;
-}
-EXPORT_SYMBOL(profile_pc);
-#endif
-
-#ifdef CONFIG_PPC_ISERIES
-
-/* 
- * This function recalibrates the timebase based on the 49-bit time-of-day
- * value in the Titan chip.  The Titan is much more accurate than the value
- * returned by the service processor for the timebase frequency.  
- */
-
-static void iSeries_tb_recal(void)
-{
-	struct div_result divres;
-	unsigned long titan, tb;
-	tb = get_tb();
-	titan = HvCallXm_loadTod();
-	if ( iSeries_recal_titan ) {
-		unsigned long tb_ticks = tb - iSeries_recal_tb;
-		unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
-		unsigned long new_tb_ticks_per_sec   = (tb_ticks * USEC_PER_SEC)/titan_usec;
-		unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
-		long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
-		char sign = '+';		
-		/* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
-		new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
-
-		if ( tick_diff < 0 ) {
-			tick_diff = -tick_diff;
-			sign = '-';
-		}
-		if ( tick_diff ) {
-			if ( tick_diff < tb_ticks_per_jiffy/25 ) {
-				printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
-						new_tb_ticks_per_jiffy, sign, tick_diff );
-				tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
-				tb_ticks_per_sec   = new_tb_ticks_per_sec;
-				div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
-				do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
-				tb_to_xs = divres.result_low;
-				do_gtod.varp->tb_to_xs = tb_to_xs;
-				systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
-				systemcfg->tb_to_xs = tb_to_xs;
-			}
-			else {
-				printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
-					"                   new tb_ticks_per_jiffy = %lu\n"
-					"                   old tb_ticks_per_jiffy = %lu\n",
-					new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
-			}
-		}
-	}
-	iSeries_recal_titan = titan;
-	iSeries_recal_tb = tb;
-}
-#endif
-
-/*
- * For iSeries shared processors, we have to let the hypervisor
- * set the hardware decrementer.  We set a virtual decrementer
- * in the lppaca and call the hypervisor if the virtual
- * decrementer is less than the current value in the hardware
- * decrementer. (almost always the new decrementer value will
- * be greater than the current hardware decementer so the hypervisor
- * call will not be needed)
- */
-
-unsigned long tb_last_stamp __cacheline_aligned_in_smp;
-
-/*
- * timer_interrupt - gets called when the decrementer overflows,
- * with interrupts disabled.
- */
-void timer_interrupt(struct pt_regs * regs)
-{
-	int next_dec;
-	unsigned long cur_tb;
-	struct paca_struct *lpaca = get_paca();
-	unsigned long cpu = smp_processor_id();
-
-	irq_enter();
-
-	profile_tick(CPU_PROFILING, regs);
-
-	lpaca->lppaca.int_dword.fields.decr_int = 0;
-
-	while (lpaca->next_jiffy_update_tb <= (cur_tb = get_tb())) {
-		/*
-		 * We cannot disable the decrementer, so in the period
-		 * between this cpu's being marked offline in cpu_online_map
-		 * and calling stop-self, it is taking timer interrupts.
-		 * Avoid calling into the scheduler rebalancing code if this
-		 * is the case.
-		 */
-		if (!cpu_is_offline(cpu))
-			update_process_times(user_mode(regs));
-		/*
-		 * No need to check whether cpu is offline here; boot_cpuid
-		 * should have been fixed up by now.
-		 */
-		if (cpu == boot_cpuid) {
-			write_seqlock(&xtime_lock);
-			tb_last_stamp = lpaca->next_jiffy_update_tb;
-			timer_recalc_offset(lpaca->next_jiffy_update_tb);
-			do_timer(regs);
-			timer_sync_xtime(lpaca->next_jiffy_update_tb);
-			timer_check_rtc();
-			write_sequnlock(&xtime_lock);
-			if ( adjusting_time && (time_adjust == 0) )
-				ppc_adjtimex();
-		}
-		lpaca->next_jiffy_update_tb += tb_ticks_per_jiffy;
-	}
-	
-	next_dec = lpaca->next_jiffy_update_tb - cur_tb;
-	if (next_dec > lpaca->default_decr)
-        	next_dec = lpaca->default_decr;
-	set_dec(next_dec);
-
-#ifdef CONFIG_PPC_ISERIES
-	if (hvlpevent_is_pending())
-		process_hvlpevents(regs);
-#endif
-
-	/* collect purr register values often, for accurate calculations */
-	if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
-		struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
-		cu->current_tb = mfspr(SPRN_PURR);
-	}
-
-	irq_exit();
-}
-
-/*
- * Scheduler clock - returns current time in nanosec units.
- *
- * Note: mulhdu(a, b) (multiply high double unsigned) returns
- * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
- * are 64-bit unsigned numbers.
- */
-unsigned long long sched_clock(void)
-{
-	return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
-}
-
-int do_settimeofday(struct timespec *tv)
-{
-	time_t wtm_sec, new_sec = tv->tv_sec;
-	long wtm_nsec, new_nsec = tv->tv_nsec;
-	unsigned long flags;
-	unsigned long delta_xsec;
-	long int tb_delta;
-	unsigned long new_xsec;
-
-	if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
-		return -EINVAL;
-
-	write_seqlock_irqsave(&xtime_lock, flags);
-	/* Updating the RTC is not the job of this code. If the time is
-	 * stepped under NTP, the RTC will be update after STA_UNSYNC
-	 * is cleared. Tool like clock/hwclock either copy the RTC
-	 * to the system time, in which case there is no point in writing
-	 * to the RTC again, or write to the RTC but then they don't call
-	 * settimeofday to perform this operation.
-	 */
-#ifdef CONFIG_PPC_ISERIES
-	if ( first_settimeofday ) {
-		iSeries_tb_recal();
-		first_settimeofday = 0;
-	}
-#endif
-	tb_delta = tb_ticks_since(tb_last_stamp);
-	tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
-
-	new_nsec -= tb_delta / tb_ticks_per_usec / 1000;
-
-	wtm_sec  = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
-	wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
-
- 	set_normalized_timespec(&xtime, new_sec, new_nsec);
-	set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
-	/* In case of a large backwards jump in time with NTP, we want the 
-	 * clock to be updated as soon as the PLL is again in lock.
-	 */
-	last_rtc_update = new_sec - 658;
-
-	ntp_clear();
-
-	delta_xsec = mulhdu( (tb_last_stamp-do_gtod.varp->tb_orig_stamp),
-			     do_gtod.varp->tb_to_xs );
-
-	new_xsec = (new_nsec * XSEC_PER_SEC) / NSEC_PER_SEC;
-	new_xsec += new_sec * XSEC_PER_SEC;
-	if ( new_xsec > delta_xsec ) {
-		do_gtod.varp->stamp_xsec = new_xsec - delta_xsec;
-		systemcfg->stamp_xsec = new_xsec - delta_xsec;
-	}
-	else {
-		/* This is only for the case where the user is setting the time
-		 * way back to a time such that the boot time would have been
-		 * before 1970 ... eg. we booted ten days ago, and we are setting
-		 * the time to Jan 5, 1970 */
-		do_gtod.varp->stamp_xsec = new_xsec;
-		do_gtod.varp->tb_orig_stamp = tb_last_stamp;
-		systemcfg->stamp_xsec = new_xsec;
-		systemcfg->tb_orig_stamp = tb_last_stamp;
-	}
-
-	systemcfg->tz_minuteswest = sys_tz.tz_minuteswest;
-	systemcfg->tz_dsttime = sys_tz.tz_dsttime;
-
-	write_sequnlock_irqrestore(&xtime_lock, flags);
-	clock_was_set();
-	return 0;
-}
-
-EXPORT_SYMBOL(do_settimeofday);
-
-#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_MAPLE) || defined(CONFIG_PPC_BPA) || defined(CONFIG_PPC_ISERIES)
-void __init generic_calibrate_decr(void)
-{
-	struct device_node *cpu;
-	struct div_result divres;
-	unsigned int *fp;
-	int node_found;
-
-	/*
-	 * The cpu node should have a timebase-frequency property
-	 * to tell us the rate at which the decrementer counts.
-	 */
-	cpu = of_find_node_by_type(NULL, "cpu");
-
-	ppc_tb_freq = DEFAULT_TB_FREQ;		/* hardcoded default */
-	node_found = 0;
-	if (cpu != 0) {
-		fp = (unsigned int *)get_property(cpu, "timebase-frequency",
-						  NULL);
-		if (fp != 0) {
-			node_found = 1;
-			ppc_tb_freq = *fp;
-		}
-	}
-	if (!node_found)
-		printk(KERN_ERR "WARNING: Estimating decrementer frequency "
-				"(not found)\n");
-
-	ppc_proc_freq = DEFAULT_PROC_FREQ;
-	node_found = 0;
-	if (cpu != 0) {
-		fp = (unsigned int *)get_property(cpu, "clock-frequency",
-						  NULL);
-		if (fp != 0) {
-			node_found = 1;
-			ppc_proc_freq = *fp;
-		}
-	}
-	if (!node_found)
-		printk(KERN_ERR "WARNING: Estimating processor frequency "
-				"(not found)\n");
-
-	of_node_put(cpu);
-
-	printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
-	       ppc_tb_freq/1000000, ppc_tb_freq%1000000);
-	printk(KERN_INFO "time_init: processor frequency   = %lu.%.6lu MHz\n",
-	       ppc_proc_freq/1000000, ppc_proc_freq%1000000);
-
-	tb_ticks_per_jiffy = ppc_tb_freq / HZ;
-	tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
-	tb_ticks_per_usec = ppc_tb_freq / 1000000;
-	tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
-	div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres);
-	tb_to_xs = divres.result_low;
-
-	setup_default_decr();
-}
-#endif
-
-void __init time_init(void)
-{
-	/* This function is only called on the boot processor */
-	unsigned long flags;
-	struct rtc_time tm;
-	struct div_result res;
-	unsigned long scale, shift;
-
-	ppc_md.calibrate_decr();
-
-	/*
-	 * Compute scale factor for sched_clock.
-	 * The calibrate_decr() function has set tb_ticks_per_sec,
-	 * which is the timebase frequency.
-	 * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
-	 * the 128-bit result as a 64.64 fixed-point number.
-	 * We then shift that number right until it is less than 1.0,
-	 * giving us the scale factor and shift count to use in
-	 * sched_clock().
-	 */
-	div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
-	scale = res.result_low;
-	for (shift = 0; res.result_high != 0; ++shift) {
-		scale = (scale >> 1) | (res.result_high << 63);
-		res.result_high >>= 1;
-	}
-	tb_to_ns_scale = scale;
-	tb_to_ns_shift = shift;
-
-#ifdef CONFIG_PPC_ISERIES
-	if (!piranha_simulator)
-#endif
-		ppc_md.get_boot_time(&tm);
-
-	write_seqlock_irqsave(&xtime_lock, flags);
-	xtime.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday,
-			      tm.tm_hour, tm.tm_min, tm.tm_sec);
-	tb_last_stamp = get_tb();
-	do_gtod.varp = &do_gtod.vars[0];
-	do_gtod.var_idx = 0;
-	do_gtod.varp->tb_orig_stamp = tb_last_stamp;
-	get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy;
-	do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
-	do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
-	do_gtod.varp->tb_to_xs = tb_to_xs;
-	do_gtod.tb_to_us = tb_to_us;
-	systemcfg->tb_orig_stamp = tb_last_stamp;
-	systemcfg->tb_update_count = 0;
-	systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
-	systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
-	systemcfg->tb_to_xs = tb_to_xs;
-
-	time_freq = 0;
-
-	xtime.tv_nsec = 0;
-	last_rtc_update = xtime.tv_sec;
-	set_normalized_timespec(&wall_to_monotonic,
-	                        -xtime.tv_sec, -xtime.tv_nsec);
-	write_sequnlock_irqrestore(&xtime_lock, flags);
-
-	/* Not exact, but the timer interrupt takes care of this */
-	set_dec(tb_ticks_per_jiffy);
-}
-
-/* 
- * After adjtimex is called, adjust the conversion of tb ticks
- * to microseconds to keep do_gettimeofday synchronized 
- * with ntpd.
- *
- * Use the time_adjust, time_freq and time_offset computed by adjtimex to 
- * adjust the frequency.
- */
-
-/* #define DEBUG_PPC_ADJTIMEX 1 */
-
-void ppc_adjtimex(void)
-{
-	unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec, new_tb_to_xs, new_xsec, new_stamp_xsec;
-	unsigned long tb_ticks_per_sec_delta;
-	long delta_freq, ltemp;
-	struct div_result divres; 
-	unsigned long flags;
-	struct gettimeofday_vars * temp_varp;
-	unsigned temp_idx;
-	long singleshot_ppm = 0;
-
-	/* Compute parts per million frequency adjustment to accomplish the time adjustment
-	   implied by time_offset to be applied over the elapsed time indicated by time_constant.
-	   Use SHIFT_USEC to get it into the same units as time_freq. */
-	if ( time_offset < 0 ) {
-		ltemp = -time_offset;
-		ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
-		ltemp >>= SHIFT_KG + time_constant;
-		ltemp = -ltemp;
-	}
-	else {
-		ltemp = time_offset;
-		ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
-		ltemp >>= SHIFT_KG + time_constant;
-	}
-	
-	/* If there is a single shot time adjustment in progress */
-	if ( time_adjust ) {
-#ifdef DEBUG_PPC_ADJTIMEX
-		printk("ppc_adjtimex: ");
-		if ( adjusting_time == 0 )
-			printk("starting ");
-		printk("single shot time_adjust = %ld\n", time_adjust);
-#endif	
-	
-		adjusting_time = 1;
-		
-		/* Compute parts per million frequency adjustment to match time_adjust */
-		singleshot_ppm = tickadj * HZ;	
-		/*
-		 * The adjustment should be tickadj*HZ to match the code in
-		 * linux/kernel/timer.c, but experiments show that this is too
-		 * large. 3/4 of tickadj*HZ seems about right
-		 */
-		singleshot_ppm -= singleshot_ppm / 4;
-		/* Use SHIFT_USEC to get it into the same units as time_freq */	
-		singleshot_ppm <<= SHIFT_USEC;
-		if ( time_adjust < 0 )
-			singleshot_ppm = -singleshot_ppm;
-	}
-	else {
-#ifdef DEBUG_PPC_ADJTIMEX
-		if ( adjusting_time )
-			printk("ppc_adjtimex: ending single shot time_adjust\n");
-#endif
-		adjusting_time = 0;
-	}
-	
-	/* Add up all of the frequency adjustments */
-	delta_freq = time_freq + ltemp + singleshot_ppm;
-	
-	/* Compute a new value for tb_ticks_per_sec based on the frequency adjustment */
-	den = 1000000 * (1 << (SHIFT_USEC - 8));
-	if ( delta_freq < 0 ) {
-		tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den;
-		new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta;
-	}
-	else {
-		tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den;
-		new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta;
-	}
-	
-#ifdef DEBUG_PPC_ADJTIMEX
-	printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm);
-	printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld  new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec);
-#endif
-				
-	/* Compute a new value of tb_to_xs (used to convert tb to microseconds and a new value of 
-	   stamp_xsec which is the time (in 1/2^20 second units) corresponding to tb_orig_stamp.  This 
-	   new value of stamp_xsec compensates for the change in frequency (implied by the new tb_to_xs)
-	   which guarantees that the current time remains the same */ 
-	write_seqlock_irqsave( &xtime_lock, flags );
-	tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
-	div128_by_32( 1024*1024, 0, new_tb_ticks_per_sec, &divres );
-	new_tb_to_xs = divres.result_low;
-	new_xsec = mulhdu( tb_ticks, new_tb_to_xs );
-
-	old_xsec = mulhdu( tb_ticks, do_gtod.varp->tb_to_xs );
-	new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
-
-	/* There are two copies of tb_to_xs and stamp_xsec so that no lock is needed to access and use these
-	   values in do_gettimeofday.  We alternate the copies and as long as a reasonable time elapses between
-	   changes, there will never be inconsistent values.  ntpd has a minimum of one minute between updates */
-
-	temp_idx = (do_gtod.var_idx == 0);
-	temp_varp = &do_gtod.vars[temp_idx];
-
-	temp_varp->tb_to_xs = new_tb_to_xs;
-	temp_varp->stamp_xsec = new_stamp_xsec;
-	temp_varp->tb_orig_stamp = do_gtod.varp->tb_orig_stamp;
-	smp_mb();
-	do_gtod.varp = temp_varp;
-	do_gtod.var_idx = temp_idx;
-
-	/*
-	 * tb_update_count is used to allow the problem state gettimeofday code
-	 * to assure itself that it sees a consistent view of the tb_to_xs and
-	 * stamp_xsec variables.  It reads the tb_update_count, then reads
-	 * tb_to_xs and stamp_xsec and then reads tb_update_count again.  If
-	 * the two values of tb_update_count match and are even then the
-	 * tb_to_xs and stamp_xsec values are consistent.  If not, then it
-	 * loops back and reads them again until this criteria is met.
-	 */
-	++(systemcfg->tb_update_count);
-	smp_wmb();
-	systemcfg->tb_to_xs = new_tb_to_xs;
-	systemcfg->stamp_xsec = new_stamp_xsec;
-	smp_wmb();
-	++(systemcfg->tb_update_count);
-
-	write_sequnlock_irqrestore( &xtime_lock, flags );
-
-}
-
-
-#define TICK_SIZE tick
-#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
-};
-
-/*
- * This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
- */
-void GregorianDay(struct rtc_time * tm)
-{
-	int leapsToDate;
-	int lastYear;
-	int day;
-	int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
-
-	lastYear=tm->tm_year-1;
-
-	/*
-	 * Number of leap corrections to apply up to end of last year
-	 */
-	leapsToDate = lastYear/4 - lastYear/100 + lastYear/400;
-
-	/*
-	 * This year is a leap year if it is divisible by 4 except when it is
-	 * divisible by 100 unless it is divisible by 400
-	 *
-	 * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be
-	 */
-	if((tm->tm_year%4==0) &&
-	   ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) &&
-	   (tm->tm_mon>2))
-	{
-		/*
-		 * We are past Feb. 29 in a leap year
-		 */
-		day=1;
-	}
-	else
-	{
-		day=0;
-	}
-
-	day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
-		   tm->tm_mday;
-
-	tm->tm_wday=day%7;
-}
-
-void to_tm(int tim, struct rtc_time * tm)
-{
-	register int    i;
-	register long   hms, day;
-
-	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;
-
-	/* Days are what is left over (+1) from all that. */
-	tm->tm_mday = day + 1;
-
-	/*
-	 * Determine the day of week
-	 */
-	GregorianDay(tm);
-}
-
-/* Auxiliary function to compute scaling factors */
-/* Actually the choice of a timebase running at 1/4 the of the bus
- * frequency giving resolution of a few tens of nanoseconds is quite nice.
- * It makes this computation very precise (27-28 bits typically) which
- * is optimistic considering the stability of most processor clock
- * oscillators and the precision with which the timebase frequency
- * is measured but does not harm.
- */
-unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) {
-        unsigned mlt=0, tmp, err;
-        /* No concern for performance, it's done once: use a stupid
-         * but safe and compact method to find the multiplier.
-         */
-  
-        for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
-                if (mulhwu(inscale, mlt|tmp) < outscale) mlt|=tmp;
-        }
-  
-        /* We might still be off by 1 for the best approximation.
-         * A side effect of this is that if outscale is too large
-         * the returned value will be zero.
-         * Many corner cases have been checked and seem to work,
-         * some might have been forgotten in the test however.
-         */
-  
-        err = inscale*(mlt+1);
-        if (err <= inscale/2) mlt++;
-        return mlt;
-  }
-
-/*
- * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
- * result.
- */
-
-void div128_by_32( unsigned long dividend_high, unsigned long dividend_low,
-		   unsigned divisor, struct div_result *dr )
-{
-	unsigned long a,b,c,d, w,x,y,z, ra,rb,rc;
-
-	a = dividend_high >> 32;
-	b = dividend_high & 0xffffffff;
-	c = dividend_low >> 32;
-	d = dividend_low & 0xffffffff;
-
-	w = a/divisor;
-	ra = (a - (w * divisor)) << 32;
-
-	x = (ra + b)/divisor;
-	rb = ((ra + b) - (x * divisor)) << 32;
-
-	y = (rb + c)/divisor;
-	rc = ((rb + b) - (y * divisor)) << 32;
-
-	z = (rc + d)/divisor;
-
-	dr->result_high = (w << 32) + x;
-	dr->result_low  = (y << 32) + z;
-
-}
-