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, 978 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
new file mode 100644
index 00000000000..d1608473075
--- /dev/null
+++ b/arch/powerpc/kernel/time.c
@@ -0,0 +1,978 @@
+/*
+ * 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/time.h>
+#include <linux/init.h>
+#include <linux/profile.h>
+#include <linux/cpu.h>
+#include <linux/security.h>
+#include <linux/percpu.h>
+#include <linux/rtc.h>
+
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/nvram.h>
+#include <asm/cache.h>
+#include <asm/machdep.h>
+#include <asm/uaccess.h>
+#include <asm/time.h>
+#include <asm/prom.h>
+#include <asm/irq.h>
+#include <asm/div64.h>
+#ifdef CONFIG_PPC64
+#include <asm/systemcfg.h>
+#include <asm/firmware.h>
+#endif
+#ifdef CONFIG_PPC_ISERIES
+#include <asm/iSeries/ItLpQueue.h>
+#include <asm/iSeries/HvCallXm.h>
+#endif
+
+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
+
+/* The decrementer counts down by 128 every 128ns on a 601. */
+#define DECREMENTER_COUNT_601	(1000000000 / HZ)
+
+#define XSEC_PER_SEC (1024*1024)
+
+#ifdef CONFIG_PPC64
+#define SCALE_XSEC(xsec, max)	(((xsec) * max) / XSEC_PER_SEC)
+#else
+/* compute ((xsec << 12) * max) >> 32 */
+#define SCALE_XSEC(xsec, max)	mulhwu((xsec) << 12, max)
+#endif
+
+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;
+u64 tb_to_xs;
+unsigned tb_to_us;
+unsigned long processor_freq;
+DEFINE_SPINLOCK(rtc_lock);
+EXPORT_SYMBOL_GPL(rtc_lock);
+
+u64 tb_to_ns_scale;
+unsigned tb_to_ns_shift;
+
+struct gettimeofday_struct do_gtod;
+
+extern unsigned long wall_jiffies;
+
+extern struct timezone sys_tz;
+static long timezone_offset;
+
+void ppc_adjtimex(void);
+
+static unsigned adjusting_time = 0;
+
+unsigned long ppc_proc_freq;
+unsigned long ppc_tb_freq;
+
+#ifdef CONFIG_PPC32	/* XXX for now */
+#define boot_cpuid	0
+#endif
+
+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 + timezone_offset, &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, u64 tb_val)
+{
+	unsigned long sec, usec;
+	u64 tb_ticks, xsec;
+	struct gettimeofday_vars *temp_varp;
+	u64 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;
+	xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs);
+	sec = xsec / XSEC_PER_SEC;
+	usec = (unsigned long)xsec & (XSEC_PER_SEC - 1);
+	usec = SCALE_XSEC(usec, 1000000);
+
+	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)
+{
+#ifdef CONFIG_PPC64
+	/* why do we do this? */
+	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;
+	}
+#endif
+}
+
+/*
+ * 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.
+ */
+static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
+			       unsigned int new_tb_to_xs)
+{
+	unsigned temp_idx;
+	struct gettimeofday_vars *temp_varp;
+
+	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->tb_orig_stamp = new_tb_stamp;
+	temp_varp->stamp_xsec = new_stamp_xsec;
+	smp_mb();
+	do_gtod.varp = temp_varp;
+	do_gtod.var_idx = temp_idx;
+
+#ifdef CONFIG_PPC64
+	/*
+	 * tb_update_count is used to allow the userspace 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_orig_stamp = new_tb_stamp;
+	systemcfg->stamp_xsec = new_stamp_xsec;
+	systemcfg->tb_to_xs = new_tb_to_xs;
+	smp_wmb();
+	++(systemcfg->tb_update_count);
+#endif
+}
+
+/*
+ * 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(u64 cur_tb)
+{
+	unsigned long offset;
+	u64 new_stamp_xsec;
+
+	offset = cur_tb - do_gtod.varp->tb_orig_stamp;
+	if ((offset & 0x80000000u) == 0)
+		return;
+	new_stamp_xsec = do_gtod.varp->stamp_xsec
+		+ mulhdu(offset, do_gtod.varp->tb_to_xs);
+	update_gtod(cur_tb, new_stamp_xsec, do_gtod.varp->tb_to_xs);
+}
+
+#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)
+ */
+
+u64 tb_last_stamp __cacheline_aligned_in_smp;
+
+/*
+ * Note that on ppc32 this only stores the bottom 32 bits of
+ * the timebase value, but that's enough to tell when a jiffy
+ * has passed.
+ */
+DEFINE_PER_CPU(unsigned long, last_jiffy);
+
+/*
+ * timer_interrupt - gets called when the decrementer overflows,
+ * with interrupts disabled.
+ */
+void timer_interrupt(struct pt_regs * regs)
+{
+	int next_dec;
+	int cpu = smp_processor_id();
+	unsigned long ticks;
+
+#ifdef CONFIG_PPC32
+	if (atomic_read(&ppc_n_lost_interrupts) != 0)
+		do_IRQ(regs);
+#endif
+
+	irq_enter();
+
+	profile_tick(CPU_PROFILING, regs);
+
+#ifdef CONFIG_PPC_ISERIES
+	get_paca()->lppaca.int_dword.fields.decr_int = 0;
+#endif
+
+	while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))
+	       >= tb_ticks_per_jiffy) {
+		/* Update last_jiffy */
+		per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy;
+		/* Handle RTCL overflow on 601 */
+		if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000)
+			per_cpu(last_jiffy, cpu) -= 1000000000;
+
+		/*
+		 * 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)
+			continue;
+
+		write_seqlock(&xtime_lock);
+		tb_last_stamp += tb_ticks_per_jiffy;
+		timer_recalc_offset(tb_last_stamp);
+		do_timer(regs);
+		timer_sync_xtime(tb_last_stamp);
+		timer_check_rtc();
+		write_sequnlock(&xtime_lock);
+		if (adjusting_time && (time_adjust == 0))
+			ppc_adjtimex();
+	}
+	
+	next_dec = tb_ticks_per_jiffy - ticks;
+	set_dec(next_dec);
+
+#ifdef CONFIG_PPC_ISERIES
+	if (hvlpevent_is_pending())
+		process_hvlpevents(regs);
+#endif
+
+#ifdef CONFIG_PPC64
+	/* 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);
+	}
+#endif
+
+	irq_exit();
+}
+
+void wakeup_decrementer(void)
+{
+	int i;
+
+	set_dec(tb_ticks_per_jiffy);
+	/*
+	 * We don't expect this to be called on a machine with a 601,
+	 * so using get_tbl is fine.
+	 */
+	tb_last_stamp = get_tb();
+	for_each_cpu(i)
+		per_cpu(last_jiffy, i) = tb_last_stamp;
+}
+
+#ifdef CONFIG_SMPxxx
+void __init smp_space_timers(unsigned int max_cpus)
+{
+	int i;
+	unsigned long offset = tb_ticks_per_jiffy / max_cpus;
+	unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
+
+	for_each_cpu(i) {
+		if (i != boot_cpuid) {
+			previous_tb += offset;
+			per_cpu(last_jiffy, i) = previous_tb;
+		}
+	}
+}
+#endif
+
+/*
+ * 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;
+	long int tb_delta;
+	u64 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 updated after STA_UNSYNC
+	 * is cleared.  Tools 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 -= 1000 * mulhwu(tb_to_us, tb_delta);
+
+	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();
+
+	new_xsec = (u64)new_nsec * XSEC_PER_SEC;
+	do_div(new_xsec, NSEC_PER_SEC);
+	new_xsec += (u64)new_sec * XSEC_PER_SEC;
+	update_gtod(tb_last_stamp, new_xsec, do_gtod.varp->tb_to_xs);
+
+#ifdef CONFIG_PPC64
+	systemcfg->tz_minuteswest = sys_tz.tz_minuteswest;
+	systemcfg->tz_dsttime = sys_tz.tz_dsttime;
+#endif
+
+	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;
+}
+#endif
+
+unsigned long get_boot_time(void)
+{
+	struct rtc_time tm;
+
+	if (ppc_md.get_boot_time)
+		return ppc_md.get_boot_time();
+	if (!ppc_md.get_rtc_time)
+		return 0;
+	ppc_md.get_rtc_time(&tm);
+	return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
+		      tm.tm_hour, tm.tm_min, tm.tm_sec);
+}
+
+/* This function is only called on the boot processor */
+void __init time_init(void)
+{
+	unsigned long flags;
+	unsigned long tm = 0;
+	struct div_result res;
+	u64 scale;
+	unsigned shift;
+
+        if (ppc_md.time_init != NULL)
+                timezone_offset = ppc_md.time_init();
+
+	ppc_md.calibrate_decr();
+
+#ifdef CONFIG_PPC64
+	get_paca()->default_decr = tb_ticks_per_jiffy;
+#endif
+
+	/*
+	 * 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
+		tm = get_boot_time();
+
+	write_seqlock_irqsave(&xtime_lock, flags);
+	xtime.tv_sec = tm;
+	xtime.tv_nsec = 0;
+	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_cpu_var(last_jiffy) = tb_last_stamp;
+	do_gtod.varp->stamp_xsec = (u64) 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;
+#ifdef CONFIG_PPC64
+	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;
+#endif
+
+	time_freq = 0;
+
+	/* If platform provided a timezone (pmac), we correct the time */
+        if (timezone_offset) {
+		sys_tz.tz_minuteswest = -timezone_offset / 60;
+		sys_tz.tz_dsttime = 0;
+		xtime.tv_sec -= timezone_offset;
+        }
+
+	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)
+{
+#ifdef CONFIG_PPC64
+	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;
+	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;
+
+	update_gtod(do_gtod.varp->tb_orig_stamp, new_stamp_xsec, new_tb_to_xs);
+
+	write_sequnlock_irqrestore( &xtime_lock, flags );
+#endif /* CONFIG_PPC64 */
+}
+
+
+#define FEBRUARY	2
+#define	STARTOFTIME	1970
+#define SECDAY		86400L
+#define SECYR		(SECDAY * 365)
+#define	leapyear(year)		((year) % 4 == 0 && \
+				 ((year) % 100 != 0 || (year) % 400 == 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 was
+	 */
+	day = tm->tm_mon > 2 && leapyear(tm->tm_year);
+
+	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(u64 dividend_high, u64 dividend_low,
+		  unsigned divisor, struct div_result *dr)
+{
+	unsigned long a, b, c, d;
+	unsigned long w, x, y, z;
+	u64 ra, rb, rc;
+
+	a = dividend_high >> 32;
+	b = dividend_high & 0xffffffff;
+	c = dividend_low >> 32;
+	d = dividend_low & 0xffffffff;
+
+	w = a / divisor;
+	ra = ((u64)(a - (w * divisor)) << 32) + b;
+
+#ifdef CONFIG_PPC64
+	x = ra / divisor;
+	rb = ((ra - (x * divisor)) << 32) + c;
+
+	y = rb / divisor;
+	rc = ((rb - (y * divisor)) << 32) + d;
+
+	z = rc / divisor;
+#else
+	/* for 32-bit, use do_div from div64.h */
+	rb = ((u64) do_div(ra, divisor) << 32) + c;
+	x = ra;
+
+	rc = ((u64) do_div(rb, divisor) << 32) + d;
+	y = rb;
+
+	do_div(rc, divisor);
+	z = rc;
+#endif
+
+	dr->result_high = ((u64)w << 32) + x;
+	dr->result_low  = ((u64)y << 32) + z;
+
+}
+