976 lines
27 KiB
C
976 lines
27 KiB
C
/*
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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/config.h>
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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 <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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#ifdef CONFIG_PPC64
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#include <asm/systemcfg.h>
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#include <asm/firmware.h>
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#endif
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#ifdef CONFIG_PPC_ISERIES
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#include <asm/iSeries/ItLpQueue.h>
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#include <asm/iSeries/HvCallXm.h>
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#endif
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u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES;
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EXPORT_SYMBOL(jiffies_64);
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/* keep track of when we need to update the rtc */
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time_t last_rtc_update;
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extern int piranha_simulator;
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#ifdef CONFIG_PPC_ISERIES
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unsigned long iSeries_recal_titan = 0;
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unsigned long iSeries_recal_tb = 0;
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static unsigned long first_settimeofday = 1;
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#endif
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/* The decrementer counts down by 128 every 128ns on a 601. */
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#define DECREMENTER_COUNT_601 (1000000000 / HZ)
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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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u64 tb_to_xs;
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unsigned tb_to_us;
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unsigned long processor_freq;
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DEFINE_SPINLOCK(rtc_lock);
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EXPORT_SYMBOL_GPL(rtc_lock);
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u64 tb_to_ns_scale;
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unsigned tb_to_ns_shift;
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struct gettimeofday_struct do_gtod;
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extern unsigned long wall_jiffies;
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extern struct timezone sys_tz;
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static long timezone_offset;
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void ppc_adjtimex(void);
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static unsigned adjusting_time = 0;
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unsigned long ppc_proc_freq;
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unsigned long ppc_tb_freq;
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#ifdef CONFIG_PPC32 /* XXX for now */
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#define boot_cpuid 0
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#endif
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static __inline__ void timer_check_rtc(void)
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{
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/*
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* update the rtc when needed, this should be performed on the
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* right fraction of a second. Half or full second ?
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* Full second works on mk48t59 clocks, others need testing.
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* Note that this update is basically only used through
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* the adjtimex system calls. Setting the HW clock in
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* any other way is a /dev/rtc and userland business.
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* This is still wrong by -0.5/+1.5 jiffies because of the
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* timer interrupt resolution and possible delay, but here we
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* hit a quantization limit which can only be solved by higher
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* resolution timers and decoupling time management from timer
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* interrupts. This is also wrong on the clocks
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* which require being written at the half second boundary.
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* We should have an rtc call that only sets the minutes and
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* seconds like on Intel to avoid problems with non UTC clocks.
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*/
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if (ntp_synced() &&
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xtime.tv_sec - last_rtc_update >= 659 &&
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abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ &&
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jiffies - wall_jiffies == 1) {
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struct rtc_time tm;
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to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
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tm.tm_year -= 1900;
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tm.tm_mon -= 1;
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if (ppc_md.set_rtc_time(&tm) == 0)
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last_rtc_update = xtime.tv_sec + 1;
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else
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/* Try again one minute later */
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last_rtc_update += 60;
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}
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}
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/*
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* This version of gettimeofday has microsecond resolution.
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*/
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static inline void __do_gettimeofday(struct timeval *tv, u64 tb_val)
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{
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unsigned long sec, usec;
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u64 tb_ticks, xsec;
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struct gettimeofday_vars *temp_varp;
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u64 temp_tb_to_xs, temp_stamp_xsec;
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/*
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* These calculations are faster (gets rid of divides)
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* if done in units of 1/2^20 rather than microseconds.
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* The conversion to microseconds at the end is done
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* without a divide (and in fact, without a multiply)
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*/
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temp_varp = do_gtod.varp;
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tb_ticks = tb_val - temp_varp->tb_orig_stamp;
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temp_tb_to_xs = temp_varp->tb_to_xs;
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temp_stamp_xsec = temp_varp->stamp_xsec;
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xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs);
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sec = xsec / XSEC_PER_SEC;
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usec = (unsigned long)xsec & (XSEC_PER_SEC - 1);
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usec = SCALE_XSEC(usec, 1000000);
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tv->tv_sec = sec;
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tv->tv_usec = usec;
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}
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void do_gettimeofday(struct timeval *tv)
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{
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__do_gettimeofday(tv, get_tb());
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}
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EXPORT_SYMBOL(do_gettimeofday);
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/* Synchronize xtime with do_gettimeofday */
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static inline void timer_sync_xtime(unsigned long cur_tb)
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{
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#ifdef CONFIG_PPC64
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/* why do we do this? */
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struct timeval my_tv;
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__do_gettimeofday(&my_tv, cur_tb);
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if (xtime.tv_sec <= my_tv.tv_sec) {
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xtime.tv_sec = my_tv.tv_sec;
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xtime.tv_nsec = my_tv.tv_usec * 1000;
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}
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#endif
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}
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/*
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* There are two copies of tb_to_xs and stamp_xsec so that no
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* lock is needed to access and use these values in
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* do_gettimeofday. We alternate the copies and as long as a
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* reasonable time elapses between changes, there will never
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* be inconsistent values. ntpd has a minimum of one minute
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* between updates.
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*/
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static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
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unsigned int new_tb_to_xs)
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{
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unsigned temp_idx;
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struct gettimeofday_vars *temp_varp;
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temp_idx = (do_gtod.var_idx == 0);
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temp_varp = &do_gtod.vars[temp_idx];
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temp_varp->tb_to_xs = new_tb_to_xs;
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temp_varp->tb_orig_stamp = new_tb_stamp;
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temp_varp->stamp_xsec = new_stamp_xsec;
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smp_mb();
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do_gtod.varp = temp_varp;
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do_gtod.var_idx = temp_idx;
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#ifdef CONFIG_PPC64
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/*
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* tb_update_count is used to allow the userspace gettimeofday code
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* to assure itself that it sees a consistent view of the tb_to_xs and
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* stamp_xsec variables. It reads the tb_update_count, then reads
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* tb_to_xs and stamp_xsec and then reads tb_update_count again. If
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* the two values of tb_update_count match and are even then the
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* tb_to_xs and stamp_xsec values are consistent. If not, then it
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* loops back and reads them again until this criteria is met.
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*/
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++(systemcfg->tb_update_count);
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smp_wmb();
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systemcfg->tb_orig_stamp = new_tb_stamp;
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systemcfg->stamp_xsec = new_stamp_xsec;
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systemcfg->tb_to_xs = new_tb_to_xs;
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smp_wmb();
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++(systemcfg->tb_update_count);
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#endif
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}
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/*
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* When the timebase - tb_orig_stamp gets too big, we do a manipulation
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* between tb_orig_stamp and stamp_xsec. The goal here is to keep the
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* difference tb - tb_orig_stamp small enough to always fit inside a
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* 32 bits number. This is a requirement of our fast 32 bits userland
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* implementation in the vdso. If we "miss" a call to this function
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* (interrupt latency, CPU locked in a spinlock, ...) and we end up
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* with a too big difference, then the vdso will fallback to calling
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* the syscall
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*/
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static __inline__ void timer_recalc_offset(u64 cur_tb)
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{
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unsigned long offset;
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u64 new_stamp_xsec;
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offset = cur_tb - do_gtod.varp->tb_orig_stamp;
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if ((offset & 0x80000000u) == 0)
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return;
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new_stamp_xsec = do_gtod.varp->stamp_xsec
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+ mulhdu(offset, do_gtod.varp->tb_to_xs);
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update_gtod(cur_tb, new_stamp_xsec, do_gtod.varp->tb_to_xs);
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}
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#ifdef CONFIG_SMP
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unsigned long profile_pc(struct pt_regs *regs)
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{
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unsigned long pc = instruction_pointer(regs);
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if (in_lock_functions(pc))
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return regs->link;
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return pc;
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}
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EXPORT_SYMBOL(profile_pc);
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#endif
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#ifdef CONFIG_PPC_ISERIES
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/*
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* This function recalibrates the timebase based on the 49-bit time-of-day
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* value in the Titan chip. The Titan is much more accurate than the value
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* returned by the service processor for the timebase frequency.
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*/
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static void iSeries_tb_recal(void)
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{
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struct div_result divres;
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unsigned long titan, tb;
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tb = get_tb();
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titan = HvCallXm_loadTod();
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if ( iSeries_recal_titan ) {
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unsigned long tb_ticks = tb - iSeries_recal_tb;
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unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12;
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unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec;
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unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ;
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long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy;
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char sign = '+';
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/* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */
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new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ;
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if ( tick_diff < 0 ) {
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tick_diff = -tick_diff;
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sign = '-';
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}
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if ( tick_diff ) {
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if ( tick_diff < tb_ticks_per_jiffy/25 ) {
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printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n",
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new_tb_ticks_per_jiffy, sign, tick_diff );
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tb_ticks_per_jiffy = new_tb_ticks_per_jiffy;
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tb_ticks_per_sec = new_tb_ticks_per_sec;
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div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres );
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do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
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tb_to_xs = divres.result_low;
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do_gtod.varp->tb_to_xs = tb_to_xs;
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systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
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systemcfg->tb_to_xs = tb_to_xs;
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}
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else {
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printk( "Titan recalibrate: FAILED (difference > 4 percent)\n"
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" new tb_ticks_per_jiffy = %lu\n"
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" old tb_ticks_per_jiffy = %lu\n",
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new_tb_ticks_per_jiffy, tb_ticks_per_jiffy );
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}
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}
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}
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iSeries_recal_titan = titan;
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iSeries_recal_tb = tb;
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}
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#endif
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/*
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* For iSeries shared processors, we have to let the hypervisor
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* set the hardware decrementer. We set a virtual decrementer
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* in the lppaca and call the hypervisor if the virtual
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* decrementer is less than the current value in the hardware
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* decrementer. (almost always the new decrementer value will
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* be greater than the current hardware decementer so the hypervisor
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* call will not be needed)
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*/
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u64 tb_last_stamp __cacheline_aligned_in_smp;
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/*
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* Note that on ppc32 this only stores the bottom 32 bits of
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* the timebase value, but that's enough to tell when a jiffy
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* has passed.
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*/
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DEFINE_PER_CPU(unsigned long, last_jiffy);
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/*
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* timer_interrupt - gets called when the decrementer overflows,
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* with interrupts disabled.
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*/
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void timer_interrupt(struct pt_regs * regs)
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{
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int next_dec;
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int cpu = smp_processor_id();
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unsigned long ticks;
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#ifdef CONFIG_PPC32
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if (atomic_read(&ppc_n_lost_interrupts) != 0)
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do_IRQ(regs);
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#endif
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irq_enter();
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profile_tick(CPU_PROFILING, regs);
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#ifdef CONFIG_PPC_ISERIES
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get_paca()->lppaca.int_dword.fields.decr_int = 0;
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#endif
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while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))
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>= tb_ticks_per_jiffy) {
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/* Update last_jiffy */
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per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy;
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/* Handle RTCL overflow on 601 */
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if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000)
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per_cpu(last_jiffy, cpu) -= 1000000000;
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/*
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* We cannot disable the decrementer, so in the period
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* between this cpu's being marked offline in cpu_online_map
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* and calling stop-self, it is taking timer interrupts.
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* Avoid calling into the scheduler rebalancing code if this
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* is the case.
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*/
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if (!cpu_is_offline(cpu))
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update_process_times(user_mode(regs));
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/*
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* No need to check whether cpu is offline here; boot_cpuid
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* should have been fixed up by now.
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*/
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if (cpu != boot_cpuid)
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continue;
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write_seqlock(&xtime_lock);
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tb_last_stamp += tb_ticks_per_jiffy;
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timer_recalc_offset(tb_last_stamp);
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do_timer(regs);
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timer_sync_xtime(tb_last_stamp);
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timer_check_rtc();
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write_sequnlock(&xtime_lock);
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if (adjusting_time && (time_adjust == 0))
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ppc_adjtimex();
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}
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next_dec = tb_ticks_per_jiffy - ticks;
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set_dec(next_dec);
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#ifdef CONFIG_PPC_ISERIES
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if (hvlpevent_is_pending())
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process_hvlpevents(regs);
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#endif
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#ifdef CONFIG_PPC64
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/* collect purr register values often, for accurate calculations */
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if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
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struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
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cu->current_tb = mfspr(SPRN_PURR);
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}
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#endif
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irq_exit();
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}
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void wakeup_decrementer(void)
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{
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int i;
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set_dec(tb_ticks_per_jiffy);
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/*
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* We don't expect this to be called on a machine with a 601,
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* so using get_tbl is fine.
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*/
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tb_last_stamp = get_tb();
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for_each_cpu(i)
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per_cpu(last_jiffy, i) = tb_last_stamp;
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}
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|
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#ifdef CONFIG_SMPxxx
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void __init smp_space_timers(unsigned int max_cpus)
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{
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int i;
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unsigned long offset = tb_ticks_per_jiffy / max_cpus;
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unsigned long previous_tb = per_cpu(last_jiffy, boot_cpuid);
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for_each_cpu(i) {
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if (i != boot_cpuid) {
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previous_tb += offset;
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per_cpu(last_jiffy, i) = previous_tb;
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}
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}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Scheduler clock - returns current time in nanosec units.
|
|
*
|
|
* Note: mulhdu(a, b) (multiply high double unsigned) returns
|
|
* the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b
|
|
* are 64-bit unsigned numbers.
|
|
*/
|
|
unsigned long long sched_clock(void)
|
|
{
|
|
return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift;
|
|
}
|
|
|
|
int do_settimeofday(struct timespec *tv)
|
|
{
|
|
time_t wtm_sec, new_sec = tv->tv_sec;
|
|
long wtm_nsec, new_nsec = tv->tv_nsec;
|
|
unsigned long flags;
|
|
long int tb_delta;
|
|
u64 new_xsec;
|
|
|
|
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
|
|
return -EINVAL;
|
|
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
|
|
|
/*
|
|
* Updating the RTC is not the job of this code. If the time is
|
|
* stepped under NTP, the RTC will be updated after STA_UNSYNC
|
|
* is cleared. Tools like clock/hwclock either copy the RTC
|
|
* to the system time, in which case there is no point in writing
|
|
* to the RTC again, or write to the RTC but then they don't call
|
|
* settimeofday to perform this operation.
|
|
*/
|
|
#ifdef CONFIG_PPC_ISERIES
|
|
if (first_settimeofday) {
|
|
iSeries_tb_recal();
|
|
first_settimeofday = 0;
|
|
}
|
|
#endif
|
|
tb_delta = tb_ticks_since(tb_last_stamp);
|
|
tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
|
|
|
|
new_nsec -= 1000 * mulhwu(tb_to_us, tb_delta);
|
|
|
|
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
|
|
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
|
|
|
|
set_normalized_timespec(&xtime, new_sec, new_nsec);
|
|
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
|
|
|
|
/* In case of a large backwards jump in time with NTP, we want the
|
|
* clock to be updated as soon as the PLL is again in lock.
|
|
*/
|
|
last_rtc_update = new_sec - 658;
|
|
|
|
ntp_clear();
|
|
|
|
new_xsec = (u64)new_nsec * XSEC_PER_SEC;
|
|
do_div(new_xsec, NSEC_PER_SEC);
|
|
new_xsec += (u64)new_sec * XSEC_PER_SEC;
|
|
update_gtod(tb_last_stamp, new_xsec, do_gtod.varp->tb_to_xs);
|
|
|
|
#ifdef CONFIG_PPC64
|
|
systemcfg->tz_minuteswest = sys_tz.tz_minuteswest;
|
|
systemcfg->tz_dsttime = sys_tz.tz_dsttime;
|
|
#endif
|
|
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
|
clock_was_set();
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(do_settimeofday);
|
|
|
|
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 != 0) {
|
|
fp = (unsigned int *)get_property(cpu, "timebase-frequency",
|
|
NULL);
|
|
if (fp != 0) {
|
|
node_found = 1;
|
|
ppc_tb_freq = *fp;
|
|
}
|
|
}
|
|
if (!node_found)
|
|
printk(KERN_ERR "WARNING: Estimating decrementer frequency "
|
|
"(not found)\n");
|
|
|
|
ppc_proc_freq = DEFAULT_PROC_FREQ;
|
|
node_found = 0;
|
|
if (cpu != 0) {
|
|
fp = (unsigned int *)get_property(cpu, "clock-frequency",
|
|
NULL);
|
|
if (fp != 0) {
|
|
node_found = 1;
|
|
ppc_proc_freq = *fp;
|
|
}
|
|
}
|
|
if (!node_found)
|
|
printk(KERN_ERR "WARNING: Estimating processor frequency "
|
|
"(not found)\n");
|
|
|
|
of_node_put(cpu);
|
|
}
|
|
|
|
unsigned long get_boot_time(void)
|
|
{
|
|
struct rtc_time tm;
|
|
|
|
if (ppc_md.get_boot_time)
|
|
return ppc_md.get_boot_time();
|
|
if (!ppc_md.get_rtc_time)
|
|
return 0;
|
|
ppc_md.get_rtc_time(&tm);
|
|
return mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday,
|
|
tm.tm_hour, tm.tm_min, tm.tm_sec);
|
|
}
|
|
|
|
/* This function is only called on the boot processor */
|
|
void __init time_init(void)
|
|
{
|
|
unsigned long flags;
|
|
unsigned long tm = 0;
|
|
struct div_result res;
|
|
u64 scale;
|
|
unsigned shift;
|
|
|
|
if (ppc_md.time_init != NULL)
|
|
timezone_offset = ppc_md.time_init();
|
|
|
|
ppc_md.calibrate_decr();
|
|
|
|
printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n",
|
|
ppc_tb_freq / 1000000, ppc_tb_freq % 1000000);
|
|
printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n",
|
|
ppc_proc_freq / 1000000, ppc_proc_freq % 1000000);
|
|
|
|
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
|
|
tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
|
|
tb_ticks_per_usec = ppc_tb_freq / 1000000;
|
|
tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
|
|
div128_by_32(1024*1024, 0, tb_ticks_per_sec, &res);
|
|
tb_to_xs = res.result_low;
|
|
|
|
#ifdef CONFIG_PPC64
|
|
get_paca()->default_decr = tb_ticks_per_jiffy;
|
|
#endif
|
|
|
|
/*
|
|
* Compute scale factor for sched_clock.
|
|
* The calibrate_decr() function has set tb_ticks_per_sec,
|
|
* which is the timebase frequency.
|
|
* We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret
|
|
* the 128-bit result as a 64.64 fixed-point number.
|
|
* We then shift that number right until it is less than 1.0,
|
|
* giving us the scale factor and shift count to use in
|
|
* sched_clock().
|
|
*/
|
|
div128_by_32(1000000000, 0, tb_ticks_per_sec, &res);
|
|
scale = res.result_low;
|
|
for (shift = 0; res.result_high != 0; ++shift) {
|
|
scale = (scale >> 1) | (res.result_high << 63);
|
|
res.result_high >>= 1;
|
|
}
|
|
tb_to_ns_scale = scale;
|
|
tb_to_ns_shift = shift;
|
|
|
|
#ifdef CONFIG_PPC_ISERIES
|
|
if (!piranha_simulator)
|
|
#endif
|
|
tm = get_boot_time();
|
|
|
|
write_seqlock_irqsave(&xtime_lock, flags);
|
|
xtime.tv_sec = tm;
|
|
xtime.tv_nsec = 0;
|
|
tb_last_stamp = get_tb();
|
|
do_gtod.varp = &do_gtod.vars[0];
|
|
do_gtod.var_idx = 0;
|
|
do_gtod.varp->tb_orig_stamp = tb_last_stamp;
|
|
__get_cpu_var(last_jiffy) = tb_last_stamp;
|
|
do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
|
|
do_gtod.tb_ticks_per_sec = tb_ticks_per_sec;
|
|
do_gtod.varp->tb_to_xs = tb_to_xs;
|
|
do_gtod.tb_to_us = tb_to_us;
|
|
#ifdef CONFIG_PPC64
|
|
systemcfg->tb_orig_stamp = tb_last_stamp;
|
|
systemcfg->tb_update_count = 0;
|
|
systemcfg->tb_ticks_per_sec = tb_ticks_per_sec;
|
|
systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
|
|
systemcfg->tb_to_xs = tb_to_xs;
|
|
#endif
|
|
|
|
time_freq = 0;
|
|
|
|
/* If platform provided a timezone (pmac), we correct the time */
|
|
if (timezone_offset) {
|
|
sys_tz.tz_minuteswest = -timezone_offset / 60;
|
|
sys_tz.tz_dsttime = 0;
|
|
xtime.tv_sec -= timezone_offset;
|
|
}
|
|
|
|
last_rtc_update = xtime.tv_sec;
|
|
set_normalized_timespec(&wall_to_monotonic,
|
|
-xtime.tv_sec, -xtime.tv_nsec);
|
|
write_sequnlock_irqrestore(&xtime_lock, flags);
|
|
|
|
/* Not exact, but the timer interrupt takes care of this */
|
|
set_dec(tb_ticks_per_jiffy);
|
|
}
|
|
|
|
/*
|
|
* After adjtimex is called, adjust the conversion of tb ticks
|
|
* to microseconds to keep do_gettimeofday synchronized
|
|
* with ntpd.
|
|
*
|
|
* Use the time_adjust, time_freq and time_offset computed by adjtimex to
|
|
* adjust the frequency.
|
|
*/
|
|
|
|
/* #define DEBUG_PPC_ADJTIMEX 1 */
|
|
|
|
void ppc_adjtimex(void)
|
|
{
|
|
#ifdef CONFIG_PPC64
|
|
unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec,
|
|
new_tb_to_xs, new_xsec, new_stamp_xsec;
|
|
unsigned long tb_ticks_per_sec_delta;
|
|
long delta_freq, ltemp;
|
|
struct div_result divres;
|
|
unsigned long flags;
|
|
long singleshot_ppm = 0;
|
|
|
|
/*
|
|
* Compute parts per million frequency adjustment to
|
|
* accomplish the time adjustment implied by time_offset to be
|
|
* applied over the elapsed time indicated by time_constant.
|
|
* Use SHIFT_USEC to get it into the same units as
|
|
* time_freq.
|
|
*/
|
|
if ( time_offset < 0 ) {
|
|
ltemp = -time_offset;
|
|
ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
ltemp = -ltemp;
|
|
} else {
|
|
ltemp = time_offset;
|
|
ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
|
|
ltemp >>= SHIFT_KG + time_constant;
|
|
}
|
|
|
|
/* If there is a single shot time adjustment in progress */
|
|
if ( time_adjust ) {
|
|
#ifdef DEBUG_PPC_ADJTIMEX
|
|
printk("ppc_adjtimex: ");
|
|
if ( adjusting_time == 0 )
|
|
printk("starting ");
|
|
printk("single shot time_adjust = %ld\n", time_adjust);
|
|
#endif
|
|
|
|
adjusting_time = 1;
|
|
|
|
/*
|
|
* Compute parts per million frequency adjustment
|
|
* to match time_adjust
|
|
*/
|
|
singleshot_ppm = tickadj * HZ;
|
|
/*
|
|
* The adjustment should be tickadj*HZ to match the code in
|
|
* linux/kernel/timer.c, but experiments show that this is too
|
|
* large. 3/4 of tickadj*HZ seems about right
|
|
*/
|
|
singleshot_ppm -= singleshot_ppm / 4;
|
|
/* Use SHIFT_USEC to get it into the same units as time_freq */
|
|
singleshot_ppm <<= SHIFT_USEC;
|
|
if ( time_adjust < 0 )
|
|
singleshot_ppm = -singleshot_ppm;
|
|
}
|
|
else {
|
|
#ifdef DEBUG_PPC_ADJTIMEX
|
|
if ( adjusting_time )
|
|
printk("ppc_adjtimex: ending single shot time_adjust\n");
|
|
#endif
|
|
adjusting_time = 0;
|
|
}
|
|
|
|
/* Add up all of the frequency adjustments */
|
|
delta_freq = time_freq + ltemp + singleshot_ppm;
|
|
|
|
/*
|
|
* Compute a new value for tb_ticks_per_sec based on
|
|
* the frequency adjustment
|
|
*/
|
|
den = 1000000 * (1 << (SHIFT_USEC - 8));
|
|
if ( delta_freq < 0 ) {
|
|
tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den;
|
|
new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta;
|
|
}
|
|
else {
|
|
tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den;
|
|
new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta;
|
|
}
|
|
|
|
#ifdef DEBUG_PPC_ADJTIMEX
|
|
printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm);
|
|
printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec);
|
|
#endif
|
|
|
|
/*
|
|
* Compute a new value of tb_to_xs (used to convert tb to
|
|
* microseconds) and a new value of stamp_xsec which is the
|
|
* time (in 1/2^20 second units) corresponding to
|
|
* tb_orig_stamp. This new value of stamp_xsec compensates
|
|
* for the change in frequency (implied by the new tb_to_xs)
|
|
* which guarantees that the current time remains the same.
|
|
*/
|
|
write_seqlock_irqsave( &xtime_lock, flags );
|
|
tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
|
|
div128_by_32(1024*1024, 0, new_tb_ticks_per_sec, &divres);
|
|
new_tb_to_xs = divres.result_low;
|
|
new_xsec = mulhdu(tb_ticks, new_tb_to_xs);
|
|
|
|
old_xsec = mulhdu(tb_ticks, do_gtod.varp->tb_to_xs);
|
|
new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
|
|
|
|
update_gtod(do_gtod.varp->tb_orig_stamp, new_stamp_xsec, new_tb_to_xs);
|
|
|
|
write_sequnlock_irqrestore( &xtime_lock, flags );
|
|
#endif /* CONFIG_PPC64 */
|
|
}
|
|
|
|
|
|
#define FEBRUARY 2
|
|
#define STARTOFTIME 1970
|
|
#define SECDAY 86400L
|
|
#define SECYR (SECDAY * 365)
|
|
#define leapyear(year) ((year) % 4 == 0 && \
|
|
((year) % 100 != 0 || (year) % 400 == 0))
|
|
#define days_in_year(a) (leapyear(a) ? 366 : 365)
|
|
#define days_in_month(a) (month_days[(a) - 1])
|
|
|
|
static int month_days[12] = {
|
|
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
|
|
};
|
|
|
|
/*
|
|
* This only works for the Gregorian calendar - i.e. after 1752 (in the UK)
|
|
*/
|
|
void GregorianDay(struct rtc_time * tm)
|
|
{
|
|
int leapsToDate;
|
|
int lastYear;
|
|
int day;
|
|
int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
|
|
|
|
lastYear = tm->tm_year - 1;
|
|
|
|
/*
|
|
* Number of leap corrections to apply up to end of last year
|
|
*/
|
|
leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400;
|
|
|
|
/*
|
|
* This year is a leap year if it is divisible by 4 except when it is
|
|
* divisible by 100 unless it is divisible by 400
|
|
*
|
|
* e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was
|
|
*/
|
|
day = tm->tm_mon > 2 && leapyear(tm->tm_year);
|
|
|
|
day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] +
|
|
tm->tm_mday;
|
|
|
|
tm->tm_wday = day % 7;
|
|
}
|
|
|
|
void to_tm(int tim, struct rtc_time * tm)
|
|
{
|
|
register int i;
|
|
register long hms, day;
|
|
|
|
day = tim / SECDAY;
|
|
hms = tim % SECDAY;
|
|
|
|
/* Hours, minutes, seconds are easy */
|
|
tm->tm_hour = hms / 3600;
|
|
tm->tm_min = (hms % 3600) / 60;
|
|
tm->tm_sec = (hms % 3600) % 60;
|
|
|
|
/* Number of years in days */
|
|
for (i = STARTOFTIME; day >= days_in_year(i); i++)
|
|
day -= days_in_year(i);
|
|
tm->tm_year = i;
|
|
|
|
/* Number of months in days left */
|
|
if (leapyear(tm->tm_year))
|
|
days_in_month(FEBRUARY) = 29;
|
|
for (i = 1; day >= days_in_month(i); i++)
|
|
day -= days_in_month(i);
|
|
days_in_month(FEBRUARY) = 28;
|
|
tm->tm_mon = i;
|
|
|
|
/* Days are what is left over (+1) from all that. */
|
|
tm->tm_mday = day + 1;
|
|
|
|
/*
|
|
* Determine the day of week
|
|
*/
|
|
GregorianDay(tm);
|
|
}
|
|
|
|
/* Auxiliary function to compute scaling factors */
|
|
/* Actually the choice of a timebase running at 1/4 the of the bus
|
|
* frequency giving resolution of a few tens of nanoseconds is quite nice.
|
|
* It makes this computation very precise (27-28 bits typically) which
|
|
* is optimistic considering the stability of most processor clock
|
|
* oscillators and the precision with which the timebase frequency
|
|
* is measured but does not harm.
|
|
*/
|
|
unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale)
|
|
{
|
|
unsigned mlt=0, tmp, err;
|
|
/* No concern for performance, it's done once: use a stupid
|
|
* but safe and compact method to find the multiplier.
|
|
*/
|
|
|
|
for (tmp = 1U<<31; tmp != 0; tmp >>= 1) {
|
|
if (mulhwu(inscale, mlt|tmp) < outscale)
|
|
mlt |= tmp;
|
|
}
|
|
|
|
/* We might still be off by 1 for the best approximation.
|
|
* A side effect of this is that if outscale is too large
|
|
* the returned value will be zero.
|
|
* Many corner cases have been checked and seem to work,
|
|
* some might have been forgotten in the test however.
|
|
*/
|
|
|
|
err = inscale * (mlt+1);
|
|
if (err <= inscale/2)
|
|
mlt++;
|
|
return mlt;
|
|
}
|
|
|
|
/*
|
|
* Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit
|
|
* result.
|
|
*/
|
|
void div128_by_32(u64 dividend_high, u64 dividend_low,
|
|
unsigned divisor, struct div_result *dr)
|
|
{
|
|
unsigned long a, b, c, d;
|
|
unsigned long w, x, y, z;
|
|
u64 ra, rb, rc;
|
|
|
|
a = dividend_high >> 32;
|
|
b = dividend_high & 0xffffffff;
|
|
c = dividend_low >> 32;
|
|
d = dividend_low & 0xffffffff;
|
|
|
|
w = a / divisor;
|
|
ra = ((u64)(a - (w * divisor)) << 32) + b;
|
|
|
|
#ifdef CONFIG_PPC64
|
|
x = ra / divisor;
|
|
rb = ((ra - (x * divisor)) << 32) + c;
|
|
|
|
y = rb / divisor;
|
|
rc = ((rb - (y * divisor)) << 32) + d;
|
|
|
|
z = rc / divisor;
|
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#else
|
|
/* for 32-bit, use do_div from div64.h */
|
|
rb = ((u64) do_div(ra, divisor) << 32) + c;
|
|
x = ra;
|
|
|
|
rc = ((u64) do_div(rb, divisor) << 32) + d;
|
|
y = rb;
|
|
|
|
do_div(rc, divisor);
|
|
z = rc;
|
|
#endif
|
|
|
|
dr->result_high = ((u64)w << 32) + x;
|
|
dr->result_low = ((u64)y << 32) + z;
|
|
|
|
}
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