Linux-2.6.12-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!
diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c
new file mode 100644
index 0000000..77ded5a
--- /dev/null
+++ b/arch/ppc64/kernel/time.c
@@ -0,0 +1,827 @@
+/*
+ *
+ * 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/segment.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>
+
+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);
+
+unsigned long tb_to_ns_scale;
+unsigned long tb_to_ns_shift;
+
+struct gettimeofday_struct do_gtod;
+
+extern unsigned long wall_jiffies;
+extern unsigned long lpevent_count;
+extern int smp_tb_synchronized;
+
+extern struct timezone sys_tz;
+
+void ppc_adjtimex(void);
+
+static unsigned adjusting_time = 0;
+
+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 ( (time_status & STA_UNSYNC) == 0 &&
+ 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;
+ mb();
+ do_gtod.varp = temp_varp;
+ do_gtod.var_idx = temp_idx;
+
+ ++(systemcfg->tb_update_count);
+ wmb();
+ systemcfg->tb_orig_stamp = new_tb_orig_stamp;
+ systemcfg->stamp_xsec = new_stamp_xsec;
+ 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.
+ */
+int 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();
+
+#ifndef CONFIG_PPC_ISERIES
+ profile_tick(CPU_PROFILING, regs);
+#endif
+
+ 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
+ {
+ struct ItLpQueue *lpq = lpaca->lpqueue_ptr;
+ if (lpq && ItLpQueue_isLpIntPending(lpq))
+ lpevent_count += ItLpQueue_process(lpq, regs);
+ }
+#endif
+
+/* collect purr register values often, for accurate calculations */
+#if defined(CONFIG_PPC_PSERIES)
+ if (cur_cpu_spec->firmware_features & FW_FEATURE_SPLPAR) {
+ struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
+ cu->current_tb = mfspr(SPRN_PURR);
+ }
+#endif
+
+ irq_exit();
+
+ return 1;
+}
+
+/*
+ * 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;
+
+ time_adjust = 0; /* stop active adjtime() */
+ time_status |= STA_UNSYNC;
+ time_maxerror = NTP_PHASE_LIMIT;
+ time_esterror = NTP_PHASE_LIMIT;
+
+ 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);
+
+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;
+ 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;
+ 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);
+ wmb();
+ systemcfg->tb_to_xs = new_tb_to_xs;
+ systemcfg->stamp_xsec = new_stamp_xsec;
+ 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;
+
+}
+