1 |
3 |
xianfeng |
/*
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* Common time routines among all ppc machines.
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*
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* Written by Cort Dougan (cort@cs.nmt.edu) to merge
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* Paul Mackerras' version and mine for PReP and Pmac.
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* MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net).
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* Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com)
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*
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* First round of bugfixes by Gabriel Paubert (paubert@iram.es)
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* to make clock more stable (2.4.0-test5). The only thing
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* that this code assumes is that the timebases have been synchronized
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* by firmware on SMP and are never stopped (never do sleep
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* on SMP then, nap and doze are OK).
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*
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* Speeded up do_gettimeofday by getting rid of references to
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* xtime (which required locks for consistency). (mikejc@us.ibm.com)
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*
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* TODO (not necessarily in this file):
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* - improve precision and reproducibility of timebase frequency
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* measurement at boot time. (for iSeries, we calibrate the timebase
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* against the Titan chip's clock.)
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* - for astronomical applications: add a new function to get
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* non ambiguous timestamps even around leap seconds. This needs
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* a new timestamp format and a good name.
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*
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/errno.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/param.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <linux/timex.h>
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#include <linux/kernel_stat.h>
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#include <linux/time.h>
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#include <linux/init.h>
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#include <linux/profile.h>
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#include <linux/cpu.h>
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#include <linux/security.h>
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#include <linux/percpu.h>
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#include <linux/rtc.h>
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#include <linux/jiffies.h>
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#include <linux/posix-timers.h>
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#include <linux/irq.h>
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#include <asm/io.h>
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#include <asm/processor.h>
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#include <asm/nvram.h>
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#include <asm/cache.h>
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#include <asm/machdep.h>
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#include <asm/uaccess.h>
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#include <asm/time.h>
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#include <asm/prom.h>
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#include <asm/irq.h>
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#include <asm/div64.h>
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#include <asm/smp.h>
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#include <asm/vdso_datapage.h>
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#include <asm/firmware.h>
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#ifdef CONFIG_PPC_ISERIES
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#include <asm/iseries/it_lp_queue.h>
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#include <asm/iseries/hv_call_xm.h>
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#endif
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/* powerpc clocksource/clockevent code */
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#include <linux/clockchips.h>
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#include <linux/clocksource.h>
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static cycle_t rtc_read(void);
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static struct clocksource clocksource_rtc = {
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.name = "rtc",
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.rating = 400,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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.mask = CLOCKSOURCE_MASK(64),
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.shift = 22,
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.mult = 0, /* To be filled in */
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.read = rtc_read,
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};
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static cycle_t timebase_read(void);
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static struct clocksource clocksource_timebase = {
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.name = "timebase",
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.rating = 400,
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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.mask = CLOCKSOURCE_MASK(64),
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.shift = 22,
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.mult = 0, /* To be filled in */
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.read = timebase_read,
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};
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#define DECREMENTER_MAX 0x7fffffff
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static int decrementer_set_next_event(unsigned long evt,
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struct clock_event_device *dev);
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static void decrementer_set_mode(enum clock_event_mode mode,
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struct clock_event_device *dev);
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static struct clock_event_device decrementer_clockevent = {
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.name = "decrementer",
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.rating = 200,
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.shift = 16,
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.mult = 0, /* To be filled in */
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.irq = 0,
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.set_next_event = decrementer_set_next_event,
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.set_mode = decrementer_set_mode,
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.features = CLOCK_EVT_FEAT_ONESHOT,
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};
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static DEFINE_PER_CPU(struct clock_event_device, decrementers);
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void init_decrementer_clockevent(void);
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static DEFINE_PER_CPU(u64, decrementer_next_tb);
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#ifdef CONFIG_PPC_ISERIES
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static unsigned long __initdata iSeries_recal_titan;
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static signed long __initdata iSeries_recal_tb;
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/* Forward declaration is only needed for iSereis compiles */
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void __init clocksource_init(void);
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#endif
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#define XSEC_PER_SEC (1024*1024)
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#ifdef CONFIG_PPC64
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#define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC)
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#else
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/* compute ((xsec << 12) * max) >> 32 */
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#define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max)
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#endif
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unsigned long tb_ticks_per_jiffy;
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unsigned long tb_ticks_per_usec = 100; /* sane default */
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EXPORT_SYMBOL(tb_ticks_per_usec);
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unsigned long tb_ticks_per_sec;
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EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */
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u64 tb_to_xs;
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unsigned tb_to_us;
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#define TICKLEN_SCALE TICK_LENGTH_SHIFT
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u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
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u64 ticklen_to_xs; /* 0.64 fraction */
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/* If last_tick_len corresponds to about 1/HZ seconds, then
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last_tick_len << TICKLEN_SHIFT will be about 2^63. */
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#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL_GPL(rtc_lock);
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static u64 tb_to_ns_scale __read_mostly;
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static unsigned tb_to_ns_shift __read_mostly;
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static unsigned long boot_tb __read_mostly;
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struct gettimeofday_struct do_gtod;
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extern struct timezone sys_tz;
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static long timezone_offset;
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unsigned long ppc_proc_freq;
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EXPORT_SYMBOL(ppc_proc_freq);
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unsigned long ppc_tb_freq;
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static u64 tb_last_jiffy __cacheline_aligned_in_smp;
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static DEFINE_PER_CPU(u64, last_jiffy);
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING
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/*
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* Factors for converting from cputime_t (timebase ticks) to
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* jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds).
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* These are all stored as 0.64 fixed-point binary fractions.
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*/
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u64 __cputime_jiffies_factor;
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EXPORT_SYMBOL(__cputime_jiffies_factor);
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u64 __cputime_msec_factor;
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EXPORT_SYMBOL(__cputime_msec_factor);
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u64 __cputime_sec_factor;
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EXPORT_SYMBOL(__cputime_sec_factor);
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u64 __cputime_clockt_factor;
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EXPORT_SYMBOL(__cputime_clockt_factor);
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static void calc_cputime_factors(void)
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{
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struct div_result res;
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div128_by_32(HZ, 0, tb_ticks_per_sec, &res);
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__cputime_jiffies_factor = res.result_low;
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div128_by_32(1000, 0, tb_ticks_per_sec, &res);
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__cputime_msec_factor = res.result_low;
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div128_by_32(1, 0, tb_ticks_per_sec, &res);
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__cputime_sec_factor = res.result_low;
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div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res);
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__cputime_clockt_factor = res.result_low;
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}
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/*
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* Read the PURR on systems that have it, otherwise the timebase.
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*/
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static u64 read_purr(void)
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{
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if (cpu_has_feature(CPU_FTR_PURR))
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return mfspr(SPRN_PURR);
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return mftb();
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}
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/*
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* Read the SPURR on systems that have it, otherwise the purr
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*/
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static u64 read_spurr(u64 purr)
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{
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if (cpu_has_feature(CPU_FTR_SPURR))
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return mfspr(SPRN_SPURR);
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return purr;
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}
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/*
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* Account time for a transition between system, hard irq
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* or soft irq state.
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*/
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void account_system_vtime(struct task_struct *tsk)
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{
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230 |
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u64 now, nowscaled, delta, deltascaled;
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231 |
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unsigned long flags;
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233 |
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local_irq_save(flags);
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now = read_purr();
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delta = now - get_paca()->startpurr;
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get_paca()->startpurr = now;
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nowscaled = read_spurr(now);
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deltascaled = nowscaled - get_paca()->startspurr;
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get_paca()->startspurr = nowscaled;
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240 |
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if (!in_interrupt()) {
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241 |
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/* deltascaled includes both user and system time.
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* Hence scale it based on the purr ratio to estimate
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* the system time */
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244 |
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if (get_paca()->user_time)
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deltascaled = deltascaled * get_paca()->system_time /
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(get_paca()->system_time + get_paca()->user_time);
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delta += get_paca()->system_time;
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get_paca()->system_time = 0;
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}
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account_system_time(tsk, 0, delta);
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get_paca()->purrdelta = delta;
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account_system_time_scaled(tsk, deltascaled);
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get_paca()->spurrdelta = deltascaled;
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local_irq_restore(flags);
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}
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256 |
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257 |
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/*
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258 |
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* Transfer the user and system times accumulated in the paca
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259 |
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* by the exception entry and exit code to the generic process
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260 |
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* user and system time records.
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261 |
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* Must be called with interrupts disabled.
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262 |
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*/
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263 |
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void account_process_tick(struct task_struct *tsk, int user_tick)
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264 |
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{
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265 |
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cputime_t utime, utimescaled;
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266 |
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267 |
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utime = get_paca()->user_time;
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get_paca()->user_time = 0;
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269 |
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account_user_time(tsk, utime);
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270 |
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271 |
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/* Estimate the scaled utime by scaling the real utime based
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272 |
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* on the last spurr to purr ratio */
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273 |
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utimescaled = utime * get_paca()->spurrdelta / get_paca()->purrdelta;
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274 |
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get_paca()->spurrdelta = get_paca()->purrdelta = 0;
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275 |
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account_user_time_scaled(tsk, utimescaled);
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276 |
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}
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277 |
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278 |
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/*
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279 |
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* Stuff for accounting stolen time.
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280 |
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*/
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281 |
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struct cpu_purr_data {
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282 |
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int initialized; /* thread is running */
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283 |
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u64 tb; /* last TB value read */
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284 |
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u64 purr; /* last PURR value read */
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285 |
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u64 spurr; /* last SPURR value read */
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286 |
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};
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287 |
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288 |
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/*
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289 |
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* Each entry in the cpu_purr_data array is manipulated only by its
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290 |
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* "owner" cpu -- usually in the timer interrupt but also occasionally
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291 |
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* in process context for cpu online. As long as cpus do not touch
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292 |
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* each others' cpu_purr_data, disabling local interrupts is
|
293 |
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* sufficient to serialize accesses.
|
294 |
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*/
|
295 |
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static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data);
|
296 |
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|
297 |
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static void snapshot_tb_and_purr(void *data)
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298 |
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{
|
299 |
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unsigned long flags;
|
300 |
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struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data);
|
301 |
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302 |
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local_irq_save(flags);
|
303 |
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p->tb = get_tb_or_rtc();
|
304 |
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p->purr = mfspr(SPRN_PURR);
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305 |
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wmb();
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306 |
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p->initialized = 1;
|
307 |
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local_irq_restore(flags);
|
308 |
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}
|
309 |
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|
310 |
|
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/*
|
311 |
|
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* Called during boot when all cpus have come up.
|
312 |
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*/
|
313 |
|
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void snapshot_timebases(void)
|
314 |
|
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{
|
315 |
|
|
if (!cpu_has_feature(CPU_FTR_PURR))
|
316 |
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return;
|
317 |
|
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on_each_cpu(snapshot_tb_and_purr, NULL, 0, 1);
|
318 |
|
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}
|
319 |
|
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|
320 |
|
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/*
|
321 |
|
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* Must be called with interrupts disabled.
|
322 |
|
|
*/
|
323 |
|
|
void calculate_steal_time(void)
|
324 |
|
|
{
|
325 |
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|
u64 tb, purr;
|
326 |
|
|
s64 stolen;
|
327 |
|
|
struct cpu_purr_data *pme;
|
328 |
|
|
|
329 |
|
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if (!cpu_has_feature(CPU_FTR_PURR))
|
330 |
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return;
|
331 |
|
|
pme = &per_cpu(cpu_purr_data, smp_processor_id());
|
332 |
|
|
if (!pme->initialized)
|
333 |
|
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return; /* this can happen in early boot */
|
334 |
|
|
tb = mftb();
|
335 |
|
|
purr = mfspr(SPRN_PURR);
|
336 |
|
|
stolen = (tb - pme->tb) - (purr - pme->purr);
|
337 |
|
|
if (stolen > 0)
|
338 |
|
|
account_steal_time(current, stolen);
|
339 |
|
|
pme->tb = tb;
|
340 |
|
|
pme->purr = purr;
|
341 |
|
|
}
|
342 |
|
|
|
343 |
|
|
#ifdef CONFIG_PPC_SPLPAR
|
344 |
|
|
/*
|
345 |
|
|
* Must be called before the cpu is added to the online map when
|
346 |
|
|
* a cpu is being brought up at runtime.
|
347 |
|
|
*/
|
348 |
|
|
static void snapshot_purr(void)
|
349 |
|
|
{
|
350 |
|
|
struct cpu_purr_data *pme;
|
351 |
|
|
unsigned long flags;
|
352 |
|
|
|
353 |
|
|
if (!cpu_has_feature(CPU_FTR_PURR))
|
354 |
|
|
return;
|
355 |
|
|
local_irq_save(flags);
|
356 |
|
|
pme = &per_cpu(cpu_purr_data, smp_processor_id());
|
357 |
|
|
pme->tb = mftb();
|
358 |
|
|
pme->purr = mfspr(SPRN_PURR);
|
359 |
|
|
pme->initialized = 1;
|
360 |
|
|
local_irq_restore(flags);
|
361 |
|
|
}
|
362 |
|
|
|
363 |
|
|
#endif /* CONFIG_PPC_SPLPAR */
|
364 |
|
|
|
365 |
|
|
#else /* ! CONFIG_VIRT_CPU_ACCOUNTING */
|
366 |
|
|
#define calc_cputime_factors()
|
367 |
|
|
#define calculate_steal_time() do { } while (0)
|
368 |
|
|
#endif
|
369 |
|
|
|
370 |
|
|
#if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR))
|
371 |
|
|
#define snapshot_purr() do { } while (0)
|
372 |
|
|
#endif
|
373 |
|
|
|
374 |
|
|
/*
|
375 |
|
|
* Called when a cpu comes up after the system has finished booting,
|
376 |
|
|
* i.e. as a result of a hotplug cpu action.
|
377 |
|
|
*/
|
378 |
|
|
void snapshot_timebase(void)
|
379 |
|
|
{
|
380 |
|
|
__get_cpu_var(last_jiffy) = get_tb_or_rtc();
|
381 |
|
|
snapshot_purr();
|
382 |
|
|
}
|
383 |
|
|
|
384 |
|
|
void __delay(unsigned long loops)
|
385 |
|
|
{
|
386 |
|
|
unsigned long start;
|
387 |
|
|
int diff;
|
388 |
|
|
|
389 |
|
|
if (__USE_RTC()) {
|
390 |
|
|
start = get_rtcl();
|
391 |
|
|
do {
|
392 |
|
|
/* the RTCL register wraps at 1000000000 */
|
393 |
|
|
diff = get_rtcl() - start;
|
394 |
|
|
if (diff < 0)
|
395 |
|
|
diff += 1000000000;
|
396 |
|
|
} while (diff < loops);
|
397 |
|
|
} else {
|
398 |
|
|
start = get_tbl();
|
399 |
|
|
while (get_tbl() - start < loops)
|
400 |
|
|
HMT_low();
|
401 |
|
|
HMT_medium();
|
402 |
|
|
}
|
403 |
|
|
}
|
404 |
|
|
EXPORT_SYMBOL(__delay);
|
405 |
|
|
|
406 |
|
|
void udelay(unsigned long usecs)
|
407 |
|
|
{
|
408 |
|
|
__delay(tb_ticks_per_usec * usecs);
|
409 |
|
|
}
|
410 |
|
|
EXPORT_SYMBOL(udelay);
|
411 |
|
|
|
412 |
|
|
|
413 |
|
|
/*
|
414 |
|
|
* There are two copies of tb_to_xs and stamp_xsec so that no
|
415 |
|
|
* lock is needed to access and use these values in
|
416 |
|
|
* do_gettimeofday. We alternate the copies and as long as a
|
417 |
|
|
* reasonable time elapses between changes, there will never
|
418 |
|
|
* be inconsistent values. ntpd has a minimum of one minute
|
419 |
|
|
* between updates.
|
420 |
|
|
*/
|
421 |
|
|
static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
|
422 |
|
|
u64 new_tb_to_xs)
|
423 |
|
|
{
|
424 |
|
|
unsigned temp_idx;
|
425 |
|
|
struct gettimeofday_vars *temp_varp;
|
426 |
|
|
|
427 |
|
|
temp_idx = (do_gtod.var_idx == 0);
|
428 |
|
|
temp_varp = &do_gtod.vars[temp_idx];
|
429 |
|
|
|
430 |
|
|
temp_varp->tb_to_xs = new_tb_to_xs;
|
431 |
|
|
temp_varp->tb_orig_stamp = new_tb_stamp;
|
432 |
|
|
temp_varp->stamp_xsec = new_stamp_xsec;
|
433 |
|
|
smp_mb();
|
434 |
|
|
do_gtod.varp = temp_varp;
|
435 |
|
|
do_gtod.var_idx = temp_idx;
|
436 |
|
|
|
437 |
|
|
/*
|
438 |
|
|
* tb_update_count is used to allow the userspace gettimeofday code
|
439 |
|
|
* to assure itself that it sees a consistent view of the tb_to_xs and
|
440 |
|
|
* stamp_xsec variables. It reads the tb_update_count, then reads
|
441 |
|
|
* tb_to_xs and stamp_xsec and then reads tb_update_count again. If
|
442 |
|
|
* the two values of tb_update_count match and are even then the
|
443 |
|
|
* tb_to_xs and stamp_xsec values are consistent. If not, then it
|
444 |
|
|
* loops back and reads them again until this criteria is met.
|
445 |
|
|
* We expect the caller to have done the first increment of
|
446 |
|
|
* vdso_data->tb_update_count already.
|
447 |
|
|
*/
|
448 |
|
|
vdso_data->tb_orig_stamp = new_tb_stamp;
|
449 |
|
|
vdso_data->stamp_xsec = new_stamp_xsec;
|
450 |
|
|
vdso_data->tb_to_xs = new_tb_to_xs;
|
451 |
|
|
vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
|
452 |
|
|
vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
|
453 |
|
|
smp_wmb();
|
454 |
|
|
++(vdso_data->tb_update_count);
|
455 |
|
|
}
|
456 |
|
|
|
457 |
|
|
#ifdef CONFIG_SMP
|
458 |
|
|
unsigned long profile_pc(struct pt_regs *regs)
|
459 |
|
|
{
|
460 |
|
|
unsigned long pc = instruction_pointer(regs);
|
461 |
|
|
|
462 |
|
|
if (in_lock_functions(pc))
|
463 |
|
|
return regs->link;
|
464 |
|
|
|
465 |
|
|
return pc;
|
466 |
|
|
}
|
467 |
|
|
EXPORT_SYMBOL(profile_pc);
|
468 |
|
|
#endif
|
469 |
|
|
|
470 |
|
|
#ifdef CONFIG_PPC_ISERIES
|
471 |
|
|
|
472 |
|
|
/*
|
473 |
|
|
* This function recalibrates the timebase based on the 49-bit time-of-day
|
474 |
|
|
* value in the Titan chip. The Titan is much more accurate than the value
|
475 |
|
|
* returned by the service processor for the timebase frequency.
|
476 |
|
|
*/
|
477 |
|
|
|
478 |
|
|
static int __init iSeries_tb_recal(void)
|
479 |
|
|
{
|
480 |
|
|
struct div_result divres;
|
481 |
|
|
unsigned long titan, tb;
|
482 |
|
|
|
483 |
|
|
/* Make sure we only run on iSeries */
|
484 |
|
|
if (!firmware_has_feature(FW_FEATURE_ISERIES))
|
485 |
|
|
return -ENODEV;
|
486 |
|
|
|
487 |
|
|
tb = get_tb();
|
488 |
|
|
titan = HvCallXm_loadTod();
|
489 |
|
|
if ( iSeries_recal_titan ) {
|
490 |
|
|
unsigned long tb_ticks = tb - iSeries_recal_tb;
|
491 |
|
|
unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
|
492 |
|
|
unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec;
|
493 |
|
|
unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
|
494 |
|
|
long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
|
495 |
|
|
char sign = '+';
|
496 |
|
|
/* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
|
497 |
|
|
new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
|
498 |
|
|
|
499 |
|
|
if ( tick_diff < 0 ) {
|
500 |
|
|
tick_diff = -tick_diff;
|
501 |
|
|
sign = '-';
|
502 |
|
|
}
|
503 |
|
|
if ( tick_diff ) {
|
504 |
|
|
if ( tick_diff < tb_ticks_per_jiffy/25 ) {
|
505 |
|
|
printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
|
506 |
|
|
new_tb_ticks_per_jiffy, sign, tick_diff );
|
507 |
|
|
tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
|
508 |
|
|
tb_ticks_per_sec = new_tb_ticks_per_sec;
|
509 |
|
|
calc_cputime_factors();
|
510 |
|
|
div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
|
511 |
|
|
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
|
512 |
|
|
tb_to_xs = divres.result_low;
|
513 |
|
|
do_gtod.varp->tb_to_xs = tb_to_xs;
|
514 |
|
|
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
|
515 |
|
|
vdso_data->tb_to_xs = tb_to_xs;
|
516 |
|
|
}
|
517 |
|
|
else {
|
518 |
|
|
printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
|
519 |
|
|
" new tb_ticks_per_jiffy = %lu\n"
|
520 |
|
|
" old tb_ticks_per_jiffy = %lu\n",
|
521 |
|
|
new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
|
522 |
|
|
}
|
523 |
|
|
}
|
524 |
|
|
}
|
525 |
|
|
iSeries_recal_titan = titan;
|
526 |
|
|
iSeries_recal_tb = tb;
|
527 |
|
|
|
528 |
|
|
/* Called here as now we know accurate values for the timebase */
|
529 |
|
|
clocksource_init();
|
530 |
|
|
return 0;
|
531 |
|
|
}
|
532 |
|
|
late_initcall(iSeries_tb_recal);
|
533 |
|
|
|
534 |
|
|
/* Called from platform early init */
|
535 |
|
|
void __init iSeries_time_init_early(void)
|
536 |
|
|
{
|
537 |
|
|
iSeries_recal_tb = get_tb();
|
538 |
|
|
iSeries_recal_titan = HvCallXm_loadTod();
|
539 |
|
|
}
|
540 |
|
|
#endif /* CONFIG_PPC_ISERIES */
|
541 |
|
|
|
542 |
|
|
/*
|
543 |
|
|
* For iSeries shared processors, we have to let the hypervisor
|
544 |
|
|
* set the hardware decrementer. We set a virtual decrementer
|
545 |
|
|
* in the lppaca and call the hypervisor if the virtual
|
546 |
|
|
* decrementer is less than the current value in the hardware
|
547 |
|
|
* decrementer. (almost always the new decrementer value will
|
548 |
|
|
* be greater than the current hardware decementer so the hypervisor
|
549 |
|
|
* call will not be needed)
|
550 |
|
|
*/
|
551 |
|
|
|
552 |
|
|
/*
|
553 |
|
|
* timer_interrupt - gets called when the decrementer overflows,
|
554 |
|
|
* with interrupts disabled.
|
555 |
|
|
*/
|
556 |
|
|
void timer_interrupt(struct pt_regs * regs)
|
557 |
|
|
{
|
558 |
|
|
struct pt_regs *old_regs;
|
559 |
|
|
int cpu = smp_processor_id();
|
560 |
|
|
struct clock_event_device *evt = &per_cpu(decrementers, cpu);
|
561 |
|
|
u64 now;
|
562 |
|
|
|
563 |
|
|
/* Ensure a positive value is written to the decrementer, or else
|
564 |
|
|
* some CPUs will continuue to take decrementer exceptions */
|
565 |
|
|
set_dec(DECREMENTER_MAX);
|
566 |
|
|
|
567 |
|
|
#ifdef CONFIG_PPC32
|
568 |
|
|
if (atomic_read(&ppc_n_lost_interrupts) != 0)
|
569 |
|
|
do_IRQ(regs);
|
570 |
|
|
#endif
|
571 |
|
|
|
572 |
|
|
now = get_tb_or_rtc();
|
573 |
|
|
if (now < per_cpu(decrementer_next_tb, cpu)) {
|
574 |
|
|
/* not time for this event yet */
|
575 |
|
|
now = per_cpu(decrementer_next_tb, cpu) - now;
|
576 |
|
|
if (now <= DECREMENTER_MAX)
|
577 |
|
|
set_dec((int)now);
|
578 |
|
|
return;
|
579 |
|
|
}
|
580 |
|
|
old_regs = set_irq_regs(regs);
|
581 |
|
|
irq_enter();
|
582 |
|
|
|
583 |
|
|
calculate_steal_time();
|
584 |
|
|
|
585 |
|
|
#ifdef CONFIG_PPC_ISERIES
|
586 |
|
|
if (firmware_has_feature(FW_FEATURE_ISERIES))
|
587 |
|
|
get_lppaca()->int_dword.fields.decr_int = 0;
|
588 |
|
|
#endif
|
589 |
|
|
|
590 |
|
|
if (evt->event_handler)
|
591 |
|
|
evt->event_handler(evt);
|
592 |
|
|
|
593 |
|
|
#ifdef CONFIG_PPC_ISERIES
|
594 |
|
|
if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
|
595 |
|
|
process_hvlpevents();
|
596 |
|
|
#endif
|
597 |
|
|
|
598 |
|
|
#ifdef CONFIG_PPC64
|
599 |
|
|
/* collect purr register values often, for accurate calculations */
|
600 |
|
|
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
|
601 |
|
|
struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
|
602 |
|
|
cu->current_tb = mfspr(SPRN_PURR);
|
603 |
|
|
}
|
604 |
|
|
#endif
|
605 |
|
|
|
606 |
|
|
irq_exit();
|
607 |
|
|
set_irq_regs(old_regs);
|
608 |
|
|
}
|
609 |
|
|
|
610 |
|
|
void wakeup_decrementer(void)
|
611 |
|
|
{
|
612 |
|
|
unsigned long ticks;
|
613 |
|
|
|
614 |
|
|
/*
|
615 |
|
|
* The timebase gets saved on sleep and restored on wakeup,
|
616 |
|
|
* so all we need to do is to reset the decrementer.
|
617 |
|
|
*/
|
618 |
|
|
ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
|
619 |
|
|
if (ticks < tb_ticks_per_jiffy)
|
620 |
|
|
ticks = tb_ticks_per_jiffy - ticks;
|
621 |
|
|
else
|
622 |
|
|
ticks = 1;
|
623 |
|
|
set_dec(ticks);
|
624 |
|
|
}
|
625 |
|
|
|
626 |
|
|
#ifdef CONFIG_SMP
|
627 |
|
|
void __init smp_space_timers(unsigned int max_cpus)
|
628 |
|
|
{
|
629 |
|
|
int i;
|
630 |
|
|
u64 previous_tb = per_cpu(last_jiffy, boot_cpuid);
|
631 |
|
|
|
632 |
|
|
/* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */
|
633 |
|
|
previous_tb -= tb_ticks_per_jiffy;
|
634 |
|
|
|
635 |
|
|
for_each_possible_cpu(i) {
|
636 |
|
|
if (i == boot_cpuid)
|
637 |
|
|
continue;
|
638 |
|
|
per_cpu(last_jiffy, i) = previous_tb;
|
639 |
|
|
}
|
640 |
|
|
}
|
641 |
|
|
#endif
|
642 |
|
|
|
643 |
|
|
/*
|
644 |
|
|
* Scheduler clock - returns current time in nanosec units.
|
645 |
|
|
*
|
646 |
|
|
* Note: mulhdu(a, b) (multiply high double unsigned) returns
|
647 |
|
|
* the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
|
648 |
|
|
* are 64-bit unsigned numbers.
|
649 |
|
|
*/
|
650 |
|
|
unsigned long long sched_clock(void)
|
651 |
|
|
{
|
652 |
|
|
if (__USE_RTC())
|
653 |
|
|
return get_rtc();
|
654 |
|
|
return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift;
|
655 |
|
|
}
|
656 |
|
|
|
657 |
|
|
static int __init get_freq(char *name, int cells, unsigned long *val)
|
658 |
|
|
{
|
659 |
|
|
struct device_node *cpu;
|
660 |
|
|
const unsigned int *fp;
|
661 |
|
|
int found = 0;
|
662 |
|
|
|
663 |
|
|
/* The cpu node should have timebase and clock frequency properties */
|
664 |
|
|
cpu = of_find_node_by_type(NULL, "cpu");
|
665 |
|
|
|
666 |
|
|
if (cpu) {
|
667 |
|
|
fp = of_get_property(cpu, name, NULL);
|
668 |
|
|
if (fp) {
|
669 |
|
|
found = 1;
|
670 |
|
|
*val = of_read_ulong(fp, cells);
|
671 |
|
|
}
|
672 |
|
|
|
673 |
|
|
of_node_put(cpu);
|
674 |
|
|
}
|
675 |
|
|
|
676 |
|
|
return found;
|
677 |
|
|
}
|
678 |
|
|
|
679 |
|
|
void __init generic_calibrate_decr(void)
|
680 |
|
|
{
|
681 |
|
|
ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */
|
682 |
|
|
|
683 |
|
|
if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) &&
|
684 |
|
|
!get_freq("timebase-frequency", 1, &ppc_tb_freq)) {
|
685 |
|
|
|
686 |
|
|
printk(KERN_ERR "WARNING: Estimating decrementer frequency "
|
687 |
|
|
"(not found)\n");
|
688 |
|
|
}
|
689 |
|
|
|
690 |
|
|
ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */
|
691 |
|
|
|
692 |
|
|
if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) &&
|
693 |
|
|
!get_freq("clock-frequency", 1, &ppc_proc_freq)) {
|
694 |
|
|
|
695 |
|
|
printk(KERN_ERR "WARNING: Estimating processor frequency "
|
696 |
|
|
"(not found)\n");
|
697 |
|
|
}
|
698 |
|
|
|
699 |
|
|
#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)
|
700 |
|
|
/* Set the time base to zero */
|
701 |
|
|
mtspr(SPRN_TBWL, 0);
|
702 |
|
|
mtspr(SPRN_TBWU, 0);
|
703 |
|
|
|
704 |
|
|
/* Clear any pending timer interrupts */
|
705 |
|
|
mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS);
|
706 |
|
|
|
707 |
|
|
/* Enable decrementer interrupt */
|
708 |
|
|
mtspr(SPRN_TCR, TCR_DIE);
|
709 |
|
|
#endif
|
710 |
|
|
}
|
711 |
|
|
|
712 |
|
|
int update_persistent_clock(struct timespec now)
|
713 |
|
|
{
|
714 |
|
|
struct rtc_time tm;
|
715 |
|
|
|
716 |
|
|
if (!ppc_md.set_rtc_time)
|
717 |
|
|
return 0;
|
718 |
|
|
|
719 |
|
|
to_tm(now.tv_sec + 1 + timezone_offset, &tm);
|
720 |
|
|
tm.tm_year -= 1900;
|
721 |
|
|
tm.tm_mon -= 1;
|
722 |
|
|
|
723 |
|
|
return ppc_md.set_rtc_time(&tm);
|
724 |
|
|
}
|
725 |
|
|
|
726 |
|
|
unsigned long read_persistent_clock(void)
|
727 |
|
|
{
|
728 |
|
|
struct rtc_time tm;
|
729 |
|
|
static int first = 1;
|
730 |
|
|
|
731 |
|
|
/* XXX this is a litle fragile but will work okay in the short term */
|
732 |
|
|
if (first) {
|
733 |
|
|
first = 0;
|
734 |
|
|
if (ppc_md.time_init)
|
735 |
|
|
timezone_offset = ppc_md.time_init();
|
736 |
|
|
|
737 |
|
|
/* get_boot_time() isn't guaranteed to be safe to call late */
|
738 |
|
|
if (ppc_md.get_boot_time)
|
739 |
|
|
return ppc_md.get_boot_time() -timezone_offset;
|
740 |
|
|
}
|
741 |
|
|
if (!ppc_md.get_rtc_time)
|
742 |
|
|
return 0;
|
743 |
|
|
ppc_md.get_rtc_time(&tm);
|
744 |
|
|
return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
|
745 |
|
|
tm.tm_hour, tm.tm_min, tm.tm_sec);
|
746 |
|
|
}
|
747 |
|
|
|
748 |
|
|
/* clocksource code */
|
749 |
|
|
static cycle_t rtc_read(void)
|
750 |
|
|
{
|
751 |
|
|
return (cycle_t)get_rtc();
|
752 |
|
|
}
|
753 |
|
|
|
754 |
|
|
static cycle_t timebase_read(void)
|
755 |
|
|
{
|
756 |
|
|
return (cycle_t)get_tb();
|
757 |
|
|
}
|
758 |
|
|
|
759 |
|
|
void update_vsyscall(struct timespec *wall_time, struct clocksource *clock)
|
760 |
|
|
{
|
761 |
|
|
u64 t2x, stamp_xsec;
|
762 |
|
|
|
763 |
|
|
if (clock != &clocksource_timebase)
|
764 |
|
|
return;
|
765 |
|
|
|
766 |
|
|
/* Make userspace gettimeofday spin until we're done. */
|
767 |
|
|
++vdso_data->tb_update_count;
|
768 |
|
|
smp_mb();
|
769 |
|
|
|
770 |
|
|
/* XXX this assumes clock->shift == 22 */
|
771 |
|
|
/* 4611686018 ~= 2^(20+64-22) / 1e9 */
|
772 |
|
|
t2x = (u64) clock->mult * 4611686018ULL;
|
773 |
|
|
stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
|
774 |
|
|
do_div(stamp_xsec, 1000000000);
|
775 |
|
|
stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
|
776 |
|
|
update_gtod(clock->cycle_last, stamp_xsec, t2x);
|
777 |
|
|
}
|
778 |
|
|
|
779 |
|
|
void update_vsyscall_tz(void)
|
780 |
|
|
{
|
781 |
|
|
/* Make userspace gettimeofday spin until we're done. */
|
782 |
|
|
++vdso_data->tb_update_count;
|
783 |
|
|
smp_mb();
|
784 |
|
|
vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
|
785 |
|
|
vdso_data->tz_dsttime = sys_tz.tz_dsttime;
|
786 |
|
|
smp_mb();
|
787 |
|
|
++vdso_data->tb_update_count;
|
788 |
|
|
}
|
789 |
|
|
|
790 |
|
|
void __init clocksource_init(void)
|
791 |
|
|
{
|
792 |
|
|
struct clocksource *clock;
|
793 |
|
|
|
794 |
|
|
if (__USE_RTC())
|
795 |
|
|
clock = &clocksource_rtc;
|
796 |
|
|
else
|
797 |
|
|
clock = &clocksource_timebase;
|
798 |
|
|
|
799 |
|
|
clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift);
|
800 |
|
|
|
801 |
|
|
if (clocksource_register(clock)) {
|
802 |
|
|
printk(KERN_ERR "clocksource: %s is already registered\n",
|
803 |
|
|
clock->name);
|
804 |
|
|
return;
|
805 |
|
|
}
|
806 |
|
|
|
807 |
|
|
printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n",
|
808 |
|
|
clock->name, clock->mult, clock->shift);
|
809 |
|
|
}
|
810 |
|
|
|
811 |
|
|
static int decrementer_set_next_event(unsigned long evt,
|
812 |
|
|
struct clock_event_device *dev)
|
813 |
|
|
{
|
814 |
|
|
__get_cpu_var(decrementer_next_tb) = get_tb_or_rtc() + evt;
|
815 |
|
|
set_dec(evt);
|
816 |
|
|
return 0;
|
817 |
|
|
}
|
818 |
|
|
|
819 |
|
|
static void decrementer_set_mode(enum clock_event_mode mode,
|
820 |
|
|
struct clock_event_device *dev)
|
821 |
|
|
{
|
822 |
|
|
if (mode != CLOCK_EVT_MODE_ONESHOT)
|
823 |
|
|
decrementer_set_next_event(DECREMENTER_MAX, dev);
|
824 |
|
|
}
|
825 |
|
|
|
826 |
|
|
static void register_decrementer_clockevent(int cpu)
|
827 |
|
|
{
|
828 |
|
|
struct clock_event_device *dec = &per_cpu(decrementers, cpu);
|
829 |
|
|
|
830 |
|
|
*dec = decrementer_clockevent;
|
831 |
|
|
dec->cpumask = cpumask_of_cpu(cpu);
|
832 |
|
|
|
833 |
|
|
printk(KERN_DEBUG "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
|
834 |
|
|
dec->name, dec->mult, dec->shift, cpu);
|
835 |
|
|
|
836 |
|
|
clockevents_register_device(dec);
|
837 |
|
|
}
|
838 |
|
|
|
839 |
|
|
void init_decrementer_clockevent(void)
|
840 |
|
|
{
|
841 |
|
|
int cpu = smp_processor_id();
|
842 |
|
|
|
843 |
|
|
decrementer_clockevent.mult = div_sc(ppc_tb_freq, NSEC_PER_SEC,
|
844 |
|
|
decrementer_clockevent.shift);
|
845 |
|
|
decrementer_clockevent.max_delta_ns =
|
846 |
|
|
clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
|
847 |
|
|
decrementer_clockevent.min_delta_ns =
|
848 |
|
|
clockevent_delta2ns(2, &decrementer_clockevent);
|
849 |
|
|
|
850 |
|
|
register_decrementer_clockevent(cpu);
|
851 |
|
|
}
|
852 |
|
|
|
853 |
|
|
void secondary_cpu_time_init(void)
|
854 |
|
|
{
|
855 |
|
|
/* FIME: Should make unrelatred change to move snapshot_timebase
|
856 |
|
|
* call here ! */
|
857 |
|
|
register_decrementer_clockevent(smp_processor_id());
|
858 |
|
|
}
|
859 |
|
|
|
860 |
|
|
/* This function is only called on the boot processor */
|
861 |
|
|
void __init time_init(void)
|
862 |
|
|
{
|
863 |
|
|
unsigned long flags;
|
864 |
|
|
struct div_result res;
|
865 |
|
|
u64 scale, x;
|
866 |
|
|
unsigned shift;
|
867 |
|
|
|
868 |
|
|
if (__USE_RTC()) {
|
869 |
|
|
/* 601 processor: dec counts down by 128 every 128ns */
|
870 |
|
|
ppc_tb_freq = 1000000000;
|
871 |
|
|
tb_last_jiffy = get_rtcl();
|
872 |
|
|
} else {
|
873 |
|
|
/* Normal PowerPC with timebase register */
|
874 |
|
|
ppc_md.calibrate_decr();
|
875 |
|
|
printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n",
|
876 |
|
|
ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
|
877 |
|
|
printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n",
|
878 |
|
|
ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
|
879 |
|
|
tb_last_jiffy = get_tb();
|
880 |
|
|
}
|
881 |
|
|
|
882 |
|
|
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
|
883 |
|
|
tb_ticks_per_sec = ppc_tb_freq;
|
884 |
|
|
tb_ticks_per_usec = ppc_tb_freq / 1000000;
|
885 |
|
|
tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
|
886 |
|
|
calc_cputime_factors();
|
887 |
|
|
|
888 |
|
|
/*
|
889 |
|
|
* Calculate the length of each tick in ns. It will not be
|
890 |
|
|
* exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
|
891 |
|
|
* We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
|
892 |
|
|
* rounded up.
|
893 |
|
|
*/
|
894 |
|
|
x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
|
895 |
|
|
do_div(x, ppc_tb_freq);
|
896 |
|
|
tick_nsec = x;
|
897 |
|
|
last_tick_len = x << TICKLEN_SCALE;
|
898 |
|
|
|
899 |
|
|
/*
|
900 |
|
|
* Compute ticklen_to_xs, which is a factor which gets multiplied
|
901 |
|
|
* by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
|
902 |
|
|
* It is computed as:
|
903 |
|
|
* ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
|
904 |
|
|
* where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
|
905 |
|
|
* which turns out to be N = 51 - SHIFT_HZ.
|
906 |
|
|
* This gives the result as a 0.64 fixed-point fraction.
|
907 |
|
|
* That value is reduced by an offset amounting to 1 xsec per
|
908 |
|
|
* 2^31 timebase ticks to avoid problems with time going backwards
|
909 |
|
|
* by 1 xsec when we do timer_recalc_offset due to losing the
|
910 |
|
|
* fractional xsec. That offset is equal to ppc_tb_freq/2^51
|
911 |
|
|
* since there are 2^20 xsec in a second.
|
912 |
|
|
*/
|
913 |
|
|
div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
|
914 |
|
|
tb_ticks_per_jiffy << SHIFT_HZ, &res);
|
915 |
|
|
div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
|
916 |
|
|
ticklen_to_xs = res.result_low;
|
917 |
|
|
|
918 |
|
|
/* Compute tb_to_xs from tick_nsec */
|
919 |
|
|
tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);
|
920 |
|
|
|
921 |
|
|
/*
|
922 |
|
|
* Compute scale factor for sched_clock.
|
923 |
|
|
* The calibrate_decr() function has set tb_ticks_per_sec,
|
924 |
|
|
* which is the timebase frequency.
|
925 |
|
|
* We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
|
926 |
|
|
* the 128-bit result as a 64.64 fixed-point number.
|
927 |
|
|
* We then shift that number right until it is less than 1.0,
|
928 |
|
|
* giving us the scale factor and shift count to use in
|
929 |
|
|
* sched_clock().
|
930 |
|
|
*/
|
931 |
|
|
div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
|
932 |
|
|
scale = res.result_low;
|
933 |
|
|
for (shift = 0; res.result_high != 0; ++shift) {
|
934 |
|
|
scale = (scale >> 1) | (res.result_high << 63);
|
935 |
|
|
res.result_high >>= 1;
|
936 |
|
|
}
|
937 |
|
|
tb_to_ns_scale = scale;
|
938 |
|
|
tb_to_ns_shift = shift;
|
939 |
|
|
/* Save the current timebase to pretty up CONFIG_PRINTK_TIME */
|
940 |
|
|
boot_tb = get_tb_or_rtc();
|
941 |
|
|
|
942 |
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
943 |
|
|
|
944 |
|
|
/* If platform provided a timezone (pmac), we correct the time */
|
945 |
|
|
if (timezone_offset) {
|
946 |
|
|
sys_tz.tz_minuteswest = -timezone_offset / 60;
|
947 |
|
|
sys_tz.tz_dsttime = 0;
|
948 |
|
|
}
|
949 |
|
|
|
950 |
|
|
do_gtod.varp = &do_gtod.vars[0];
|
951 |
|
|
do_gtod.var_idx = 0;
|
952 |
|
|
do_gtod.varp->tb_orig_stamp = tb_last_jiffy;
|
953 |
|
|
__get_cpu_var(last_jiffy) = tb_last_jiffy;
|
954 |
|
|
do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
|
955 |
|
|
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
|
956 |
|
|
do_gtod.varp->tb_to_xs = tb_to_xs;
|
957 |
|
|
do_gtod.tb_to_us = tb_to_us;
|
958 |
|
|
|
959 |
|
|
vdso_data->tb_orig_stamp = tb_last_jiffy;
|
960 |
|
|
vdso_data->tb_update_count = 0;
|
961 |
|
|
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
|
962 |
|
|
vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
|
963 |
|
|
vdso_data->tb_to_xs = tb_to_xs;
|
964 |
|
|
|
965 |
|
|
time_freq = 0;
|
966 |
|
|
|
967 |
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
968 |
|
|
|
969 |
|
|
/* Register the clocksource, if we're not running on iSeries */
|
970 |
|
|
if (!firmware_has_feature(FW_FEATURE_ISERIES))
|
971 |
|
|
clocksource_init();
|
972 |
|
|
|
973 |
|
|
init_decrementer_clockevent();
|
974 |
|
|
}
|
975 |
|
|
|
976 |
|
|
|
977 |
|
|
#define FEBRUARY 2
|
978 |
|
|
#define STARTOFTIME 1970
|
979 |
|
|
#define SECDAY 86400L
|
980 |
|
|
#define SECYR (SECDAY * 365)
|
981 |
|
|
#define leapyear(year) ((year) % 4 == 0 && \
|
982 |
|
|
((year) % 100 != 0 || (year) % 400 == 0))
|
983 |
|
|
#define days_in_year(a) (leapyear(a) ? 366 : 365)
|
984 |
|
|
#define days_in_month(a) (month_days[(a) - 1])
|
985 |
|
|
|
986 |
|
|
static int month_days[12] = {
|
987 |
|
|
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
|
988 |
|
|
};
|
989 |
|
|
|
990 |
|
|
/*
|
991 |
|
|
* This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
|
992 |
|
|
*/
|
993 |
|
|
void GregorianDay(struct rtc_time * tm)
|
994 |
|
|
{
|
995 |
|
|
int leapsToDate;
|
996 |
|
|
int lastYear;
|
997 |
|
|
int day;
|
998 |
|
|
int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
|
999 |
|
|
|
1000 |
|
|
lastYear = tm->tm_year - 1;
|
1001 |
|
|
|
1002 |
|
|
/*
|
1003 |
|
|
* Number of leap corrections to apply up to end of last year
|
1004 |
|
|
*/
|
1005 |
|
|
leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
|
1006 |
|
|
|
1007 |
|
|
/*
|
1008 |
|
|
* This year is a leap year if it is divisible by 4 except when it is
|
1009 |
|
|
* divisible by 100 unless it is divisible by 400
|
1010 |
|
|
*
|
1011 |
|
|
* e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
|
1012 |
|
|
*/
|
1013 |
|
|
day = tm->tm_mon > 2 && leapyear(tm->tm_year);
|
1014 |
|
|
|
1015 |
|
|
day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
|
1016 |
|
|
tm->tm_mday;
|
1017 |
|
|
|
1018 |
|
|
tm->tm_wday = day % 7;
|
1019 |
|
|
}
|
1020 |
|
|
|
1021 |
|
|
void to_tm(int tim, struct rtc_time * tm)
|
1022 |
|
|
{
|
1023 |
|
|
register int i;
|
1024 |
|
|
register long hms, day;
|
1025 |
|
|
|
1026 |
|
|
day = tim / SECDAY;
|
1027 |
|
|
hms = tim % SECDAY;
|
1028 |
|
|
|
1029 |
|
|
/* Hours, minutes, seconds are easy */
|
1030 |
|
|
tm->tm_hour = hms / 3600;
|
1031 |
|
|
tm->tm_min = (hms % 3600) / 60;
|
1032 |
|
|
tm->tm_sec = (hms % 3600) % 60;
|
1033 |
|
|
|
1034 |
|
|
/* Number of years in days */
|
1035 |
|
|
for (i = STARTOFTIME; day >= days_in_year(i); i++)
|
1036 |
|
|
day -= days_in_year(i);
|
1037 |
|
|
tm->tm_year = i;
|
1038 |
|
|
|
1039 |
|
|
/* Number of months in days left */
|
1040 |
|
|
if (leapyear(tm->tm_year))
|
1041 |
|
|
days_in_month(FEBRUARY) = 29;
|
1042 |
|
|
for (i = 1; day >= days_in_month(i); i++)
|
1043 |
|
|
day -= days_in_month(i);
|
1044 |
|
|
days_in_month(FEBRUARY) = 28;
|
1045 |
|
|
tm->tm_mon = i;
|
1046 |
|
|
|
1047 |
|
|
/* Days are what is left over (+1) from all that. */
|
1048 |
|
|
tm->tm_mday = day + 1;
|
1049 |
|
|
|
1050 |
|
|
/*
|
1051 |
|
|
* Determine the day of week
|
1052 |
|
|
*/
|
1053 |
|
|
GregorianDay(tm);
|
1054 |
|
|
}
|
1055 |
|
|
|
1056 |
|
|
/* Auxiliary function to compute scaling factors */
|
1057 |
|
|
/* Actually the choice of a timebase running at 1/4 the of the bus
|
1058 |
|
|
* frequency giving resolution of a few tens of nanoseconds is quite nice.
|
1059 |
|
|
* It makes this computation very precise (27-28 bits typically) which
|
1060 |
|
|
* is optimistic considering the stability of most processor clock
|
1061 |
|
|
* oscillators and the precision with which the timebase frequency
|
1062 |
|
|
* is measured but does not harm.
|
1063 |
|
|
*/
|
1064 |
|
|
unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
|
1065 |
|
|
{
|
1066 |
|
|
unsigned mlt=0, tmp, err;
|
1067 |
|
|
/* No concern for performance, it's done once: use a stupid
|
1068 |
|
|
* but safe and compact method to find the multiplier.
|
1069 |
|
|
*/
|
1070 |
|
|
|
1071 |
|
|
for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
|
1072 |
|
|
if (mulhwu(inscale, mlt|tmp) < outscale)
|
1073 |
|
|
mlt |= tmp;
|
1074 |
|
|
}
|
1075 |
|
|
|
1076 |
|
|
/* We might still be off by 1 for the best approximation.
|
1077 |
|
|
* A side effect of this is that if outscale is too large
|
1078 |
|
|
* the returned value will be zero.
|
1079 |
|
|
* Many corner cases have been checked and seem to work,
|
1080 |
|
|
* some might have been forgotten in the test however.
|
1081 |
|
|
*/
|
1082 |
|
|
|
1083 |
|
|
err = inscale * (mlt+1);
|
1084 |
|
|
if (err <= inscale/2)
|
1085 |
|
|
mlt++;
|
1086 |
|
|
return mlt;
|
1087 |
|
|
}
|
1088 |
|
|
|
1089 |
|
|
/*
|
1090 |
|
|
* Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
|
1091 |
|
|
* result.
|
1092 |
|
|
*/
|
1093 |
|
|
void div128_by_32(u64 dividend_high, u64 dividend_low,
|
1094 |
|
|
unsigned divisor, struct div_result *dr)
|
1095 |
|
|
{
|
1096 |
|
|
unsigned long a, b, c, d;
|
1097 |
|
|
unsigned long w, x, y, z;
|
1098 |
|
|
u64 ra, rb, rc;
|
1099 |
|
|
|
1100 |
|
|
a = dividend_high >> 32;
|
1101 |
|
|
b = dividend_high & 0xffffffff;
|
1102 |
|
|
c = dividend_low >> 32;
|
1103 |
|
|
d = dividend_low & 0xffffffff;
|
1104 |
|
|
|
1105 |
|
|
w = a / divisor;
|
1106 |
|
|
ra = ((u64)(a - (w * divisor)) << 32) + b;
|
1107 |
|
|
|
1108 |
|
|
rb = ((u64) do_div(ra, divisor) << 32) + c;
|
1109 |
|
|
x = ra;
|
1110 |
|
|
|
1111 |
|
|
rc = ((u64) do_div(rb, divisor) << 32) + d;
|
1112 |
|
|
y = rb;
|
1113 |
|
|
|
1114 |
|
|
do_div(rc, divisor);
|
1115 |
|
|
z = rc;
|
1116 |
|
|
|
1117 |
|
|
dr->result_high = ((u64)w << 32) + x;
|
1118 |
|
|
dr->result_low = ((u64)y << 32) + z;
|
1119 |
|
|
|
1120 |
|
|
}
|