--- /dev/null
+/*
+ * 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 <linux/jiffies.h>
+#include <linux/posix-timers.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>
+#include <asm/smp.h>
+#include <asm/vdso_datapage.h>
+#ifdef CONFIG_PPC64
+#include <asm/firmware.h>
+#endif
+#ifdef CONFIG_PPC_ISERIES
+#include <asm/iseries/it_lp_queue.h>
+#include <asm/iseries/hv_call_xm.h>
+#endif
+#include <asm/smp.h>
+
+/* 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;
+EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
+u64 tb_to_xs;
+unsigned tb_to_us;
+
+#define TICKLEN_SCALE (SHIFT_SCALE - 10)
+u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
+u64 ticklen_to_xs; /* 0.64 fraction */
+
+/* If last_tick_len corresponds to about 1/HZ seconds, then
+ last_tick_len << TICKLEN_SHIFT will be about 2^63. */
+#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
+
+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;
+
+unsigned long ppc_proc_freq;
+unsigned long ppc_tb_freq;
+
+u64 tb_last_jiffy __cacheline_aligned_in_smp;
+unsigned long tb_last_stamp;
+
+/*
+ * 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);
+
+#ifdef CONFIG_VIRT_CPU_ACCOUNTING
+/*
+ * Factors for converting from cputime_t (timebase ticks) to
+ * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
+ * These are all stored as 0.64 fixed-point binary fractions.
+ */
+u64 __cputime_jiffies_factor;
+EXPORT_SYMBOL(__cputime_jiffies_factor);
+u64 __cputime_msec_factor;
+EXPORT_SYMBOL(__cputime_msec_factor);
+u64 __cputime_sec_factor;
+EXPORT_SYMBOL(__cputime_sec_factor);
+u64 __cputime_clockt_factor;
+EXPORT_SYMBOL(__cputime_clockt_factor);
+
+static void calc_cputime_factors(void)
+{
+ struct div_result res;
+
+ div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_jiffies_factor = res.result_low;
+ div128_by_32(1000, 0, tb_ticks_per_sec, &res);
+ __cputime_msec_factor = res.result_low;
+ div128_by_32(1, 0, tb_ticks_per_sec, &res);
+ __cputime_sec_factor = res.result_low;
+ div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
+ __cputime_clockt_factor = res.result_low;
+}
+
+/*
+ * Read the PURR on systems that have it, otherwise the timebase.
+ */
+static u64 read_purr(void)
+{
+ if (cpu_has_feature(CPU_FTR_PURR))
+ return mfspr(SPRN_PURR);
+ return mftb();
+}
+
+/*
+ * Account time for a transition between system, hard irq
+ * or soft irq state.
+ */
+void account_system_vtime(struct task_struct *tsk)
+{
+ u64 now, delta;
+ unsigned long flags;
+
+ local_irq_save(flags);
+ now = read_purr();
+ delta = now - get_paca()->startpurr;
+ get_paca()->startpurr = now;
+ if (!in_interrupt()) {
+ delta += get_paca()->system_time;
+ get_paca()->system_time = 0;
+ }
+ account_system_time(tsk, 0, delta);
+ local_irq_restore(flags);
+}
+
+/*
+ * Transfer the user and system times accumulated in the paca
+ * by the exception entry and exit code to the generic process
+ * user and system time records.
+ * Must be called with interrupts disabled.
+ */
+void account_process_vtime(struct task_struct *tsk)
+{
+ cputime_t utime;
+
+ utime = get_paca()->user_time;
+ get_paca()->user_time = 0;
+ account_user_time(tsk, utime);
+}
+
+static void account_process_time(struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+
+ account_process_vtime(current);
+ run_local_timers();
+ if (rcu_pending(cpu))
+ rcu_check_callbacks(cpu, user_mode(regs));
+ scheduler_tick();
+ run_posix_cpu_timers(current);
+}
+
+#ifdef CONFIG_PPC_SPLPAR
+/*
+ * Stuff for accounting stolen time.
+ */
+struct cpu_purr_data {
+ int initialized; /* thread is running */
+ u64 tb0; /* timebase at origin time */
+ u64 purr0; /* PURR at origin time */
+ u64 tb; /* last TB value read */
+ u64 purr; /* last PURR value read */
+ u64 stolen; /* stolen time so far */
+ spinlock_t lock;
+};
+
+static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
+
+static void snapshot_tb_and_purr(void *data)
+{
+ struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
+
+ p->tb0 = mftb();
+ p->purr0 = mfspr(SPRN_PURR);
+ p->tb = p->tb0;
+ p->purr = 0;
+ wmb();
+ p->initialized = 1;
+}
+
+/*
+ * Called during boot when all cpus have come up.
+ */
+void snapshot_timebases(void)
+{
+ int cpu;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ for_each_possible_cpu(cpu)
+ spin_lock_init(&per_cpu(cpu_purr_data, cpu).lock);
+ on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1);
+}
+
+void calculate_steal_time(void)
+{
+ u64 tb, purr, t0;
+ s64 stolen;
+ struct cpu_purr_data *p0, *pme, *phim;
+ int cpu;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ cpu = smp_processor_id();
+ pme = &per_cpu(cpu_purr_data, cpu);
+ if (!pme->initialized)
+ return; /* this can happen in early boot */
+ p0 = &per_cpu(cpu_purr_data, cpu & ~1);
+ phim = &per_cpu(cpu_purr_data, cpu ^ 1);
+ spin_lock(&p0->lock);
+ tb = mftb();
+ purr = mfspr(SPRN_PURR) - pme->purr0;
+ if (!phim->initialized || !cpu_online(cpu ^ 1)) {
+ stolen = (tb - pme->tb) - (purr - pme->purr);
+ } else {
+ t0 = pme->tb0;
+ if (phim->tb0 < t0)
+ t0 = phim->tb0;
+ stolen = phim->tb - t0 - phim->purr - purr - p0->stolen;
+ }
+ if (stolen > 0) {
+ account_steal_time(current, stolen);
+ p0->stolen += stolen;
+ }
+ pme->tb = tb;
+ pme->purr = purr;
+ spin_unlock(&p0->lock);
+}
+
+/*
+ * Must be called before the cpu is added to the online map when
+ * a cpu is being brought up at runtime.
+ */
+static void snapshot_purr(void)
+{
+ int cpu;
+ u64 purr;
+ struct cpu_purr_data *p0, *pme, *phim;
+ unsigned long flags;
+
+ if (!cpu_has_feature(CPU_FTR_PURR))
+ return;
+ cpu = smp_processor_id();
+ pme = &per_cpu(cpu_purr_data, cpu);
+ p0 = &per_cpu(cpu_purr_data, cpu & ~1);
+ phim = &per_cpu(cpu_purr_data, cpu ^ 1);
+ spin_lock_irqsave(&p0->lock, flags);
+ pme->tb = pme->tb0 = mftb();
+ purr = mfspr(SPRN_PURR);
+ if (!phim->initialized) {
+ pme->purr = 0;
+ pme->purr0 = purr;
+ } else {
+ /* set p->purr and p->purr0 for no change in p0->stolen */
+ pme->purr = phim->tb - phim->tb0 - phim->purr - p0->stolen;
+ pme->purr0 = purr - pme->purr;
+ }
+ pme->initialized = 1;
+ spin_unlock_irqrestore(&p0->lock, flags);
+}
+
+#endif /* CONFIG_PPC_SPLPAR */
+
+#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
+#define calc_cputime_factors()
+#define account_process_time(regs) update_process_times(user_mode(regs))
+#define calculate_steal_time() do { } while (0)
+#endif
+
+#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
+#define snapshot_purr() do { } while (0)
+#endif
+
+/*
+ * Called when a cpu comes up after the system has finished booting,
+ * i.e. as a result of a hotplug cpu action.
+ */
+void snapshot_timebase(void)
+{
+ __get_cpu_var(last_jiffy) = get_tb();
+ snapshot_purr();
+}
+
+void __delay(unsigned long loops)
+{
+ unsigned long start;
+ int diff;
+
+ if (__USE_RTC()) {
+ start = get_rtcl();
+ do {
+ /* the RTCL register wraps at 1000000000 */
+ diff = get_rtcl() - start;
+ if (diff < 0)
+ diff += 1000000000;
+ } while (diff < loops);
+ } else {
+ start = get_tbl();
+ while (get_tbl() - start < loops)
+ HMT_low();
+ HMT_medium();
+ }
+}
+EXPORT_SYMBOL(__delay);
+
+void udelay(unsigned long usecs)
+{
+ __delay(tb_ticks_per_usec * usecs);
+}
+EXPORT_SYMBOL(udelay);
+
+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 (ppc_md.set_rtc_time && ntp_synced() &&
+ xtime.tv_sec - last_rtc_update >= 659 &&
+ abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) {
+ 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)
+{
+ if (__USE_RTC()) {
+ /* do this the old way */
+ unsigned long flags, seq;
+ unsigned int sec, nsec, usec;
+
+ do {
+ seq = read_seqbegin_irqsave(&xtime_lock, flags);
+ sec = xtime.tv_sec;
+ nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
+ } while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
+ usec = nsec / 1000;
+ while (usec >= 1000000) {
+ usec -= 1000000;
+ ++sec;
+ }
+ tv->tv_sec = sec;
+ tv->tv_usec = usec;
+ return;
+ }
+ __do_gettimeofday(tv, get_tb());
+}
+
+EXPORT_SYMBOL(do_gettimeofday);
+
+/*
+ * 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,
+ u64 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;
+
+ /*
+ * 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.
+ * We expect the caller to have done the first increment of
+ * vdso_data->tb_update_count already.
+ */
+ vdso_data->tb_orig_stamp = new_tb_stamp;
+ vdso_data->stamp_xsec = new_stamp_xsec;
+ vdso_data->tb_to_xs = new_tb_to_xs;
+ vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+ vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+ smp_wmb();
+ ++(vdso_data->tb_update_count);
+}
+
+/*
+ * 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;
+ u64 tlen, t2x;
+ u64 tb, xsec_old, xsec_new;
+ struct gettimeofday_vars *varp;
+
+ if (__USE_RTC())
+ return;
+ tlen = current_tick_length();
+ offset = cur_tb - do_gtod.varp->tb_orig_stamp;
+ if (tlen == last_tick_len && offset < 0x80000000u)
+ return;
+ if (tlen != last_tick_len) {
+ t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs);
+ last_tick_len = tlen;
+ } else
+ t2x = do_gtod.varp->tb_to_xs;
+ new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+ do_div(new_stamp_xsec, 1000000000);
+ new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
+
+ ++vdso_data->tb_update_count;
+ smp_mb();
+
+ /*
+ * Make sure time doesn't go backwards for userspace gettimeofday.
+ */
+ tb = get_tb();
+ varp = do_gtod.varp;
+ xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs)
+ + varp->stamp_xsec;
+ xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec;
+ if (xsec_new < xsec_old)
+ new_stamp_xsec += xsec_old - xsec_new;
+
+ update_gtod(cur_tb, new_stamp_xsec, t2x);
+}
+
+#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;
+ calc_cputime_factors();
+ 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;
+ vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
+ vdso_data->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)
+ */
+
+/*
+ * 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);
+ calculate_steal_time();
+
+#ifdef CONFIG_PPC_ISERIES
+ get_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))
+ account_process_time(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_jiffy += tb_ticks_per_jiffy;
+ tb_last_stamp = per_cpu(last_jiffy, cpu);
+ do_timer(regs);
+ timer_recalc_offset(tb_last_jiffy);
+ timer_check_rtc();
+ write_sequnlock(&xtime_lock);
+ }
+
+ 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)
+{
+ unsigned long ticks;
+
+ /*
+ * The timebase gets saved on sleep and restored on wakeup,
+ * so all we need to do is to reset the decrementer.
+ */
+ ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
+ if (ticks < tb_ticks_per_jiffy)
+ ticks = tb_ticks_per_jiffy - ticks;
+ else
+ ticks = 1;
+ set_dec(ticks);
+}
+
+#ifdef CONFIG_SMP
+void __init smp_space_timers(unsigned int max_cpus)
+{
+ int i;
+ unsigned long half = tb_ticks_per_jiffy / 2;
+ unsigned long offset = tb_ticks_per_jiffy / max_cpus;
+ unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
+
+ /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
+ previous_tb -= tb_ticks_per_jiffy;
+ /*
+ * The stolen time calculation for POWER5 shared-processor LPAR
+ * systems works better if the two threads' timebase interrupts
+ * are staggered by half a jiffy with respect to each other.
+ */
+ for_each_possible_cpu(i) {
+ if (i == boot_cpuid)
+ continue;
+ if (i == (boot_cpuid ^ 1))
+ per_cpu(last_jiffy, i) =
+ per_cpu(last_jiffy, boot_cpuid) - half;
+ else if (i & 1)
+ per_cpu(last_jiffy, i) =
+ per_cpu(last_jiffy, i ^ 1) + half;
+ else {
+ 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)
+{
+ if (__USE_RTC())
+ return get_rtc();
+ 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;
+ u64 new_xsec;
+ unsigned long tb_delta;
+
+ 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
+
+ /* Make userspace gettimeofday spin until we're done. */
+ ++vdso_data->tb_update_count;
+ smp_mb();
+
+ /*
+ * Subtract off the number of nanoseconds since the
+ * beginning of the last tick.
+ * Note that since we don't increment jiffies_64 anywhere other
+ * than in do_timer (since we don't have a lost tick problem),
+ * wall_jiffies will always be the same as jiffies,
+ * and therefore the (jiffies - wall_jiffies) computation
+ * has been removed.
+ */
+ tb_delta = tb_ticks_since(tb_last_stamp);
+ tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */
+ new_nsec -= SCALE_XSEC(tb_delta, 1000000000);
+
+ 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 = xtime.tv_nsec;
+ if (new_xsec != 0) {
+ new_xsec *= XSEC_PER_SEC;
+ do_div(new_xsec, NSEC_PER_SEC);
+ }
+ new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC;
+ update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
+
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ clock_was_set();
+ return 0;
+}
+
+EXPORT_SYMBOL(do_settimeofday);
+
+void __init generic_calibrate_decr(void)
+{
+ struct device_node *cpu;
+ 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) {
+ fp = (unsigned int *)get_property(cpu, "timebase-frequency",
+ NULL);
+ if (fp) {
+ 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) {
+ fp = (unsigned int *)get_property(cpu, "clock-frequency",
+ NULL);
+ if (fp) {
+ node_found = 1;
+ ppc_proc_freq = *fp;
+ }
+ }
+#ifdef CONFIG_BOOKE
+ /* Set the time base to zero */
+ mtspr(SPRN_TBWL, 0);
+ mtspr(SPRN_TBWU, 0);
+
+ /* Clear any pending timer interrupts */
+ mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
+
+ /* Enable decrementer interrupt */
+ mtspr(SPRN_TCR, TCR_DIE);
+#endif
+ if (!node_found)
+ printk(KERN_ERR "WARNING: Estimating processor frequency "
+ "(not found)\n");
+
+ of_node_put(cpu);
+}
+
+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, x;
+ unsigned shift;
+
+ if (ppc_md.time_init != NULL)
+ timezone_offset = ppc_md.time_init();
+
+ if (__USE_RTC()) {
+ /* 601 processor: dec counts down by 128 every 128ns */
+ ppc_tb_freq = 1000000000;
+ tb_last_stamp = get_rtcl();
+ tb_last_jiffy = tb_last_stamp;
+ } else {
+ /* Normal PowerPC with timebase register */
+ ppc_md.calibrate_decr();
+ 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_last_stamp = tb_last_jiffy = get_tb();
+ }
+
+ tb_ticks_per_jiffy = ppc_tb_freq / HZ;
+ tb_ticks_per_sec = ppc_tb_freq;
+ tb_ticks_per_usec = ppc_tb_freq / 1000000;
+ tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
+ calc_cputime_factors();
+
+ /*
+ * Calculate the length of each tick in ns. It will not be
+ * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
+ * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
+ * rounded up.
+ */
+ x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
+ do_div(x, ppc_tb_freq);
+ tick_nsec = x;
+ last_tick_len = x << TICKLEN_SCALE;
+
+ /*
+ * Compute ticklen_to_xs, which is a factor which gets multiplied
+ * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
+ * It is computed as:
+ * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
+ * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
+ * which turns out to be N = 51 - SHIFT_HZ.
+ * This gives the result as a 0.64 fixed-point fraction.
+ * That value is reduced by an offset amounting to 1 xsec per
+ * 2^31 timebase ticks to avoid problems with time going backwards
+ * by 1 xsec when we do timer_recalc_offset due to losing the
+ * fractional xsec. That offset is equal to ppc_tb_freq/2^51
+ * since there are 2^20 xsec in a second.
+ */
+ div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
+ tb_ticks_per_jiffy << SHIFT_HZ, &res);
+ div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
+ ticklen_to_xs = res.result_low;
+
+ /* Compute tb_to_xs from tick_nsec */
+ tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);
+
+ /*
+ * 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);
+
+ /* 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;
+ tm -= timezone_offset;
+ }
+
+ xtime.tv_sec = tm;
+ xtime.tv_nsec = 0;
+ do_gtod.varp = &do_gtod.vars[0];
+ do_gtod.var_idx = 0;
+ do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
+ __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;
+
+ vdso_data->tb_orig_stamp = tb_last_jiffy;
+ vdso_data->tb_update_count = 0;
+ vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
+ vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
+ vdso_data->tb_to_xs = tb_to_xs;
+
+ time_freq = 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);
+}
+
+
+#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;
+
+ 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;
+
+ dr->result_high = ((u64)w << 32) + x;
+ dr->result_low = ((u64)y << 32) + z;
+
+}
git://git.onelab.eu / linux-2.6.git / blobdiff