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Diffstat (limited to 'arch/ppc64/kernel/time.c')
| -rw-r--r-- | arch/ppc64/kernel/time.c | 879 |
1 files changed, 0 insertions, 879 deletions
diff --git a/arch/ppc64/kernel/time.c b/arch/ppc64/kernel/time.c deleted file mode 100644 index 7f63755eddfd..000000000000 --- a/arch/ppc64/kernel/time.c +++ /dev/null @@ -1,879 +0,0 @@ -/* - * - * Common time routines among all ppc machines. - * - * Written by Cort Dougan (cort@cs.nmt.edu) to merge - * Paul Mackerras' version and mine for PReP and Pmac. - * MPC8xx/MBX changes by Dan Malek (dmalek@jlc.net). - * Converted for 64-bit by Mike Corrigan (mikejc@us.ibm.com) - * - * First round of bugfixes by Gabriel Paubert (paubert@iram.es) - * to make clock more stable (2.4.0-test5). The only thing - * that this code assumes is that the timebases have been synchronized - * by firmware on SMP and are never stopped (never do sleep - * on SMP then, nap and doze are OK). - * - * Speeded up do_gettimeofday by getting rid of references to - * xtime (which required locks for consistency). (mikejc@us.ibm.com) - * - * TODO (not necessarily in this file): - * - improve precision and reproducibility of timebase frequency - * measurement at boot time. (for iSeries, we calibrate the timebase - * against the Titan chip's clock.) - * - for astronomical applications: add a new function to get - * non ambiguous timestamps even around leap seconds. This needs - * a new timestamp format and a good name. - * - * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 - * "A Kernel Model for Precision Timekeeping" by Dave Mills - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; either version - * 2 of the License, or (at your option) any later version. - */ - -#include <linux/config.h> -#include <linux/errno.h> -#include <linux/module.h> -#include <linux/sched.h> -#include <linux/kernel.h> -#include <linux/param.h> -#include <linux/string.h> -#include <linux/mm.h> -#include <linux/interrupt.h> -#include <linux/timex.h> -#include <linux/kernel_stat.h> -#include <linux/mc146818rtc.h> -#include <linux/time.h> -#include <linux/init.h> -#include <linux/profile.h> -#include <linux/cpu.h> -#include <linux/security.h> - -#include <asm/io.h> -#include <asm/processor.h> -#include <asm/nvram.h> -#include <asm/cache.h> -#include <asm/machdep.h> -#ifdef CONFIG_PPC_ISERIES -#include <asm/iSeries/ItLpQueue.h> -#include <asm/iSeries/HvCallXm.h> -#endif -#include <asm/uaccess.h> -#include <asm/time.h> -#include <asm/ppcdebug.h> -#include <asm/prom.h> -#include <asm/sections.h> -#include <asm/systemcfg.h> -#include <asm/firmware.h> - -u64 jiffies_64 __cacheline_aligned_in_smp = INITIAL_JIFFIES; - -EXPORT_SYMBOL(jiffies_64); - -/* keep track of when we need to update the rtc */ -time_t last_rtc_update; -extern int piranha_simulator; -#ifdef CONFIG_PPC_ISERIES -unsigned long iSeries_recal_titan = 0; -unsigned long iSeries_recal_tb = 0; -static unsigned long first_settimeofday = 1; -#endif - -#define XSEC_PER_SEC (1024*1024) - -unsigned long tb_ticks_per_jiffy; -unsigned long tb_ticks_per_usec = 100; /* sane default */ -EXPORT_SYMBOL(tb_ticks_per_usec); -unsigned long tb_ticks_per_sec; -unsigned long tb_to_xs; -unsigned tb_to_us; -unsigned long processor_freq; -DEFINE_SPINLOCK(rtc_lock); -EXPORT_SYMBOL_GPL(rtc_lock); - -unsigned long tb_to_ns_scale; -unsigned long tb_to_ns_shift; - -struct gettimeofday_struct do_gtod; - -extern unsigned long wall_jiffies; -extern int smp_tb_synchronized; - -extern struct timezone sys_tz; - -void ppc_adjtimex(void); - -static unsigned adjusting_time = 0; - -unsigned long ppc_proc_freq; -unsigned long ppc_tb_freq; - -static __inline__ void timer_check_rtc(void) -{ - /* - * update the rtc when needed, this should be performed on the - * right fraction of a second. Half or full second ? - * Full second works on mk48t59 clocks, others need testing. - * Note that this update is basically only used through - * the adjtimex system calls. Setting the HW clock in - * any other way is a /dev/rtc and userland business. - * This is still wrong by -0.5/+1.5 jiffies because of the - * timer interrupt resolution and possible delay, but here we - * hit a quantization limit which can only be solved by higher - * resolution timers and decoupling time management from timer - * interrupts. This is also wrong on the clocks - * which require being written at the half second boundary. - * We should have an rtc call that only sets the minutes and - * seconds like on Intel to avoid problems with non UTC clocks. - */ - if (ntp_synced() && - xtime.tv_sec - last_rtc_update >= 659 && - abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ && - jiffies - wall_jiffies == 1) { - struct rtc_time tm; - to_tm(xtime.tv_sec+1, &tm); - tm.tm_year -= 1900; - tm.tm_mon -= 1; - if (ppc_md.set_rtc_time(&tm) == 0) - last_rtc_update = xtime.tv_sec+1; - else - /* Try again one minute later */ - last_rtc_update += 60; - } -} - -/* - * This version of gettimeofday has microsecond resolution. - */ -static inline void __do_gettimeofday(struct timeval *tv, unsigned long tb_val) -{ - unsigned long sec, usec, tb_ticks; - unsigned long xsec, tb_xsec; - struct gettimeofday_vars * temp_varp; - unsigned long temp_tb_to_xs, temp_stamp_xsec; - - /* - * These calculations are faster (gets rid of divides) - * if done in units of 1/2^20 rather than microseconds. - * The conversion to microseconds at the end is done - * without a divide (and in fact, without a multiply) - */ - temp_varp = do_gtod.varp; - tb_ticks = tb_val - temp_varp->tb_orig_stamp; - temp_tb_to_xs = temp_varp->tb_to_xs; - temp_stamp_xsec = temp_varp->stamp_xsec; - tb_xsec = mulhdu( tb_ticks, temp_tb_to_xs ); - xsec = temp_stamp_xsec + tb_xsec; - sec = xsec / XSEC_PER_SEC; - xsec -= sec * XSEC_PER_SEC; - usec = (xsec * USEC_PER_SEC)/XSEC_PER_SEC; - - tv->tv_sec = sec; - tv->tv_usec = usec; -} - -void do_gettimeofday(struct timeval *tv) -{ - __do_gettimeofday(tv, get_tb()); -} - -EXPORT_SYMBOL(do_gettimeofday); - -/* Synchronize xtime with do_gettimeofday */ - -static inline void timer_sync_xtime(unsigned long cur_tb) -{ - struct timeval my_tv; - - __do_gettimeofday(&my_tv, cur_tb); - - if (xtime.tv_sec <= my_tv.tv_sec) { - xtime.tv_sec = my_tv.tv_sec; - xtime.tv_nsec = my_tv.tv_usec * 1000; - } -} - -/* - * When the timebase - tb_orig_stamp gets too big, we do a manipulation - * between tb_orig_stamp and stamp_xsec. The goal here is to keep the - * difference tb - tb_orig_stamp small enough to always fit inside a - * 32 bits number. This is a requirement of our fast 32 bits userland - * implementation in the vdso. If we "miss" a call to this function - * (interrupt latency, CPU locked in a spinlock, ...) and we end up - * with a too big difference, then the vdso will fallback to calling - * the syscall - */ -static __inline__ void timer_recalc_offset(unsigned long cur_tb) -{ - struct gettimeofday_vars * temp_varp; - unsigned temp_idx; - unsigned long offset, new_stamp_xsec, new_tb_orig_stamp; - - if (((cur_tb - do_gtod.varp->tb_orig_stamp) & 0x80000000u) == 0) - return; - - temp_idx = (do_gtod.var_idx == 0); - temp_varp = &do_gtod.vars[temp_idx]; - - new_tb_orig_stamp = cur_tb; - offset = new_tb_orig_stamp - do_gtod.varp->tb_orig_stamp; - new_stamp_xsec = do_gtod.varp->stamp_xsec + mulhdu(offset, do_gtod.varp->tb_to_xs); - - temp_varp->tb_to_xs = do_gtod.varp->tb_to_xs; - temp_varp->tb_orig_stamp = new_tb_orig_stamp; - temp_varp->stamp_xsec = new_stamp_xsec; - smp_mb(); - do_gtod.varp = temp_varp; - do_gtod.var_idx = temp_idx; - - ++(systemcfg->tb_update_count); - smp_wmb(); - systemcfg->tb_orig_stamp = new_tb_orig_stamp; - systemcfg->stamp_xsec = new_stamp_xsec; - smp_wmb(); - ++(systemcfg->tb_update_count); -} - -#ifdef CONFIG_SMP -unsigned long profile_pc(struct pt_regs *regs) -{ - unsigned long pc = instruction_pointer(regs); - - if (in_lock_functions(pc)) - return regs->link; - - return pc; -} -EXPORT_SYMBOL(profile_pc); -#endif - -#ifdef CONFIG_PPC_ISERIES - -/* - * This function recalibrates the timebase based on the 49-bit time-of-day - * value in the Titan chip. The Titan is much more accurate than the value - * returned by the service processor for the timebase frequency. - */ - -static void iSeries_tb_recal(void) -{ - struct div_result divres; - unsigned long titan, tb; - tb = get_tb(); - titan = HvCallXm_loadTod(); - if ( iSeries_recal_titan ) { - unsigned long tb_ticks = tb - iSeries_recal_tb; - unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; - unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; - unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; - long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; - char sign = '+'; - /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ - new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; - - if ( tick_diff < 0 ) { - tick_diff = -tick_diff; - sign = '-'; - } - if ( tick_diff ) { - if ( tick_diff < tb_ticks_per_jiffy/25 ) { - printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", - new_tb_ticks_per_jiffy, sign, tick_diff ); - tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; - tb_ticks_per_sec = new_tb_ticks_per_sec; - div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); - do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; - tb_to_xs = divres.result_low; - do_gtod.varp->tb_to_xs = tb_to_xs; - systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; - systemcfg->tb_to_xs = tb_to_xs; - } - else { - printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" - " new tb_ticks_per_jiffy = %lu\n" - " old tb_ticks_per_jiffy = %lu\n", - new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); - } - } - } - iSeries_recal_titan = titan; - iSeries_recal_tb = tb; -} -#endif - -/* - * For iSeries shared processors, we have to let the hypervisor - * set the hardware decrementer. We set a virtual decrementer - * in the lppaca and call the hypervisor if the virtual - * decrementer is less than the current value in the hardware - * decrementer. (almost always the new decrementer value will - * be greater than the current hardware decementer so the hypervisor - * call will not be needed) - */ - -unsigned long tb_last_stamp __cacheline_aligned_in_smp; - -/* - * timer_interrupt - gets called when the decrementer overflows, - * with interrupts disabled. - */ -void timer_interrupt(struct pt_regs * regs) -{ - int next_dec; - unsigned long cur_tb; - struct paca_struct *lpaca = get_paca(); - unsigned long cpu = smp_processor_id(); - - irq_enter(); - - profile_tick(CPU_PROFILING, regs); - - lpaca->lppaca.int_dword.fields.decr_int = 0; - - while (lpaca->next_jiffy_update_tb <= (cur_tb = get_tb())) { - /* - * We cannot disable the decrementer, so in the period - * between this cpu's being marked offline in cpu_online_map - * and calling stop-self, it is taking timer interrupts. - * Avoid calling into the scheduler rebalancing code if this - * is the case. - */ - if (!cpu_is_offline(cpu)) - update_process_times(user_mode(regs)); - /* - * No need to check whether cpu is offline here; boot_cpuid - * should have been fixed up by now. - */ - if (cpu == boot_cpuid) { - write_seqlock(&xtime_lock); - tb_last_stamp = lpaca->next_jiffy_update_tb; - timer_recalc_offset(lpaca->next_jiffy_update_tb); - do_timer(regs); - timer_sync_xtime(lpaca->next_jiffy_update_tb); - timer_check_rtc(); - write_sequnlock(&xtime_lock); - if ( adjusting_time && (time_adjust == 0) ) - ppc_adjtimex(); - } - lpaca->next_jiffy_update_tb += tb_ticks_per_jiffy; - } - - next_dec = lpaca->next_jiffy_update_tb - cur_tb; - if (next_dec > lpaca->default_decr) - next_dec = lpaca->default_decr; - set_dec(next_dec); - -#ifdef CONFIG_PPC_ISERIES - if (hvlpevent_is_pending()) - process_hvlpevents(regs); -#endif - - /* collect purr register values often, for accurate calculations */ - if (firmware_has_feature(FW_FEATURE_SPLPAR)) { - struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); - cu->current_tb = mfspr(SPRN_PURR); - } - - irq_exit(); -} - -/* - * Scheduler clock - returns current time in nanosec units. - * - * Note: mulhdu(a, b) (multiply high double unsigned) returns - * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b - * are 64-bit unsigned numbers. - */ -unsigned long long sched_clock(void) -{ - return mulhdu(get_tb(), tb_to_ns_scale) << tb_to_ns_shift; -} - -int do_settimeofday(struct timespec *tv) -{ - time_t wtm_sec, new_sec = tv->tv_sec; - long wtm_nsec, new_nsec = tv->tv_nsec; - unsigned long flags; - unsigned long delta_xsec; - long int tb_delta; - unsigned long new_xsec; - - if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; - - write_seqlock_irqsave(&xtime_lock, flags); - /* Updating the RTC is not the job of this code. If the time is - * stepped under NTP, the RTC will be update after STA_UNSYNC - * is cleared. Tool like clock/hwclock either copy the RTC - * to the system time, in which case there is no point in writing - * to the RTC again, or write to the RTC but then they don't call - * settimeofday to perform this operation. - */ -#ifdef CONFIG_PPC_ISERIES - if ( first_settimeofday ) { - iSeries_tb_recal(); - first_settimeofday = 0; - } -#endif - tb_delta = tb_ticks_since(tb_last_stamp); - tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy; - - new_nsec -= tb_delta / tb_ticks_per_usec / 1000; - - wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec); - wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec); - - set_normalized_timespec(&xtime, new_sec, new_nsec); - set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); - - /* In case of a large backwards jump in time with NTP, we want the - * clock to be updated as soon as the PLL is again in lock. - */ - last_rtc_update = new_sec - 658; - - ntp_clear(); - - delta_xsec = mulhdu( (tb_last_stamp-do_gtod.varp->tb_orig_stamp), - do_gtod.varp->tb_to_xs ); - - new_xsec = (new_nsec * XSEC_PER_SEC) / NSEC_PER_SEC; - new_xsec += new_sec * XSEC_PER_SEC; - if ( new_xsec > delta_xsec ) { - do_gtod.varp->stamp_xsec = new_xsec - delta_xsec; - systemcfg->stamp_xsec = new_xsec - delta_xsec; - } - else { - /* This is only for the case where the user is setting the time - * way back to a time such that the boot time would have been - * before 1970 ... eg. we booted ten days ago, and we are setting - * the time to Jan 5, 1970 */ - do_gtod.varp->stamp_xsec = new_xsec; - do_gtod.varp->tb_orig_stamp = tb_last_stamp; - systemcfg->stamp_xsec = new_xsec; - systemcfg->tb_orig_stamp = tb_last_stamp; - } - - systemcfg->tz_minuteswest = sys_tz.tz_minuteswest; - systemcfg->tz_dsttime = sys_tz.tz_dsttime; - - write_sequnlock_irqrestore(&xtime_lock, flags); - clock_was_set(); - return 0; -} - -EXPORT_SYMBOL(do_settimeofday); - -#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_MAPLE) || defined(CONFIG_PPC_BPA) || defined(CONFIG_PPC_ISERIES) -void __init generic_calibrate_decr(void) -{ - struct device_node *cpu; - struct div_result divres; - unsigned int *fp; - int node_found; - - /* - * The cpu node should have a timebase-frequency property - * to tell us the rate at which the decrementer counts. - */ - cpu = of_find_node_by_type(NULL, "cpu"); - - ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ - node_found = 0; - if (cpu != 0) { - fp = (unsigned int *)get_property(cpu, "timebase-frequency", - NULL); - if (fp != 0) { - node_found = 1; - ppc_tb_freq = *fp; - } - } - if (!node_found) - printk(KERN_ERR "WARNING: Estimating decrementer frequency " - "(not found)\n"); - - ppc_proc_freq = DEFAULT_PROC_FREQ; - node_found = 0; - if (cpu != 0) { - fp = (unsigned int *)get_property(cpu, "clock-frequency", - NULL); - if (fp != 0) { - node_found = 1; - ppc_proc_freq = *fp; - } - } - if (!node_found) - printk(KERN_ERR "WARNING: Estimating processor frequency " - "(not found)\n"); - - of_node_put(cpu); - - printk(KERN_INFO "time_init: decrementer frequency = %lu.%.6lu MHz\n", - ppc_tb_freq/1000000, ppc_tb_freq%1000000); - printk(KERN_INFO "time_init: processor frequency = %lu.%.6lu MHz\n", - ppc_proc_freq/1000000, ppc_proc_freq%1000000); - - tb_ticks_per_jiffy = ppc_tb_freq / HZ; - tb_ticks_per_sec = tb_ticks_per_jiffy * HZ; - tb_ticks_per_usec = ppc_tb_freq / 1000000; - tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); - div128_by_32(1024*1024, 0, tb_ticks_per_sec, &divres); - tb_to_xs = divres.result_low; - - setup_default_decr(); -} -#endif - -void __init time_init(void) -{ - /* This function is only called on the boot processor */ - unsigned long flags; - struct rtc_time tm; - struct div_result res; - unsigned long scale, shift; - - ppc_md.calibrate_decr(); - - /* - * Compute scale factor for sched_clock. - * The calibrate_decr() function has set tb_ticks_per_sec, - * which is the timebase frequency. - * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret - * the 128-bit result as a 64.64 fixed-point number. - * We then shift that number right until it is less than 1.0, - * giving us the scale factor and shift count to use in - * sched_clock(). - */ - div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); - scale = res.result_low; - for (shift = 0; res.result_high != 0; ++shift) { - scale = (scale >> 1) | (res.result_high << 63); - res.result_high >>= 1; - } - tb_to_ns_scale = scale; - tb_to_ns_shift = shift; - -#ifdef CONFIG_PPC_ISERIES - if (!piranha_simulator) -#endif - ppc_md.get_boot_time(&tm); - - write_seqlock_irqsave(&xtime_lock, flags); - xtime.tv_sec = mktime(tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, - tm.tm_hour, tm.tm_min, tm.tm_sec); - tb_last_stamp = get_tb(); - do_gtod.varp = &do_gtod.vars[0]; - do_gtod.var_idx = 0; - do_gtod.varp->tb_orig_stamp = tb_last_stamp; - get_paca()->next_jiffy_update_tb = tb_last_stamp + tb_ticks_per_jiffy; - do_gtod.varp->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; - do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; - do_gtod.varp->tb_to_xs = tb_to_xs; - do_gtod.tb_to_us = tb_to_us; - systemcfg->tb_orig_stamp = tb_last_stamp; - systemcfg->tb_update_count = 0; - systemcfg->tb_ticks_per_sec = tb_ticks_per_sec; - systemcfg->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC; - systemcfg->tb_to_xs = tb_to_xs; - - time_freq = 0; - - xtime.tv_nsec = 0; - last_rtc_update = xtime.tv_sec; - set_normalized_timespec(&wall_to_monotonic, - -xtime.tv_sec, -xtime.tv_nsec); - write_sequnlock_irqrestore(&xtime_lock, flags); - - /* Not exact, but the timer interrupt takes care of this */ - set_dec(tb_ticks_per_jiffy); -} - -/* - * After adjtimex is called, adjust the conversion of tb ticks - * to microseconds to keep do_gettimeofday synchronized - * with ntpd. - * - * Use the time_adjust, time_freq and time_offset computed by adjtimex to - * adjust the frequency. - */ - -/* #define DEBUG_PPC_ADJTIMEX 1 */ - -void ppc_adjtimex(void) -{ - unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec, new_tb_to_xs, new_xsec, new_stamp_xsec; - unsigned long tb_ticks_per_sec_delta; - long delta_freq, ltemp; - struct div_result divres; - unsigned long flags; - struct gettimeofday_vars * temp_varp; - unsigned temp_idx; - long singleshot_ppm = 0; - - /* Compute parts per million frequency adjustment to accomplish the time adjustment - implied by time_offset to be applied over the elapsed time indicated by time_constant. - Use SHIFT_USEC to get it into the same units as time_freq. */ - if ( time_offset < 0 ) { - ltemp = -time_offset; - ltemp <<= SHIFT_USEC - SHIFT_UPDATE; - ltemp >>= SHIFT_KG + time_constant; - ltemp = -ltemp; - } - else { - ltemp = time_offset; - ltemp <<= SHIFT_USEC - SHIFT_UPDATE; - ltemp >>= SHIFT_KG + time_constant; - } - - /* If there is a single shot time adjustment in progress */ - if ( time_adjust ) { -#ifdef DEBUG_PPC_ADJTIMEX - printk("ppc_adjtimex: "); - if ( adjusting_time == 0 ) - printk("starting "); - printk("single shot time_adjust = %ld\n", time_adjust); -#endif - - adjusting_time = 1; - - /* Compute parts per million frequency adjustment to match time_adjust */ - singleshot_ppm = tickadj * HZ; - /* - * The adjustment should be tickadj*HZ to match the code in - * linux/kernel/timer.c, but experiments show that this is too - * large. 3/4 of tickadj*HZ seems about right - */ - singleshot_ppm -= singleshot_ppm / 4; - /* Use SHIFT_USEC to get it into the same units as time_freq */ - singleshot_ppm <<= SHIFT_USEC; - if ( time_adjust < 0 ) - singleshot_ppm = -singleshot_ppm; - } - else { -#ifdef DEBUG_PPC_ADJTIMEX - if ( adjusting_time ) - printk("ppc_adjtimex: ending single shot time_adjust\n"); -#endif - adjusting_time = 0; - } - - /* Add up all of the frequency adjustments */ - delta_freq = time_freq + ltemp + singleshot_ppm; - - /* Compute a new value for tb_ticks_per_sec based on the frequency adjustment */ - den = 1000000 * (1 << (SHIFT_USEC - 8)); - if ( delta_freq < 0 ) { - tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den; - new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta; - } - else { - tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den; - new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta; - } - -#ifdef DEBUG_PPC_ADJTIMEX - printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm); - printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec); -#endif - - /* Compute a new value of tb_to_xs (used to convert tb to microseconds and a new value of - stamp_xsec which is the time (in 1/2^20 second units) corresponding to tb_orig_stamp. This - new value of stamp_xsec compensates for the change in frequency (implied by the new tb_to_xs) - which guarantees that the current time remains the same */ - write_seqlock_irqsave( &xtime_lock, flags ); - tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp; - div128_by_32( 1024*1024, 0, new_tb_ticks_per_sec, &divres ); - new_tb_to_xs = divres.result_low; - new_xsec = mulhdu( tb_ticks, new_tb_to_xs ); - - old_xsec = mulhdu( tb_ticks, do_gtod.varp->tb_to_xs ); - new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec; - - /* There are two copies of tb_to_xs and stamp_xsec so that no lock is needed to access and use these - values in do_gettimeofday. We alternate the copies and as long as a reasonable time elapses between - changes, there will never be inconsistent values. ntpd has a minimum of one minute between updates */ - - temp_idx = (do_gtod.var_idx == 0); - temp_varp = &do_gtod.vars[temp_idx]; - - temp_varp->tb_to_xs = new_tb_to_xs; - temp_varp->stamp_xsec = new_stamp_xsec; - temp_varp->tb_orig_stamp = do_gtod.varp->tb_orig_stamp; - smp_mb(); - do_gtod.varp = temp_varp; - do_gtod.var_idx = temp_idx; - - /* - * tb_update_count is used to allow the problem state gettimeofday code - * to assure itself that it sees a consistent view of the tb_to_xs and - * stamp_xsec variables. It reads the tb_update_count, then reads - * tb_to_xs and stamp_xsec and then reads tb_update_count again. If - * the two values of tb_update_count match and are even then the - * tb_to_xs and stamp_xsec values are consistent. If not, then it - * loops back and reads them again until this criteria is met. - */ - ++(systemcfg->tb_update_count); - smp_wmb(); - systemcfg->tb_to_xs = new_tb_to_xs; - systemcfg->stamp_xsec = new_stamp_xsec; - smp_wmb(); - ++(systemcfg->tb_update_count); - - write_sequnlock_irqrestore( &xtime_lock, flags ); - -} - - -#define TICK_SIZE tick -#define FEBRUARY 2 -#define STARTOFTIME 1970 -#define SECDAY 86400L -#define SECYR (SECDAY * 365) -#define leapyear(year) ((year) % 4 == 0) -#define days_in_year(a) (leapyear(a) ? 366 : 365) -#define days_in_month(a) (month_days[(a) - 1]) - -static int month_days[12] = { - 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 -}; - -/* - * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) - */ -void GregorianDay(struct rtc_time * tm) -{ - int leapsToDate; - int lastYear; - int day; - int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; - - lastYear=tm->tm_year-1; - - /* - * Number of leap corrections to apply up to end of last year - */ - leapsToDate = lastYear/4 - lastYear/100 + lastYear/400; - - /* - * This year is a leap year if it is divisible by 4 except when it is - * divisible by 100 unless it is divisible by 400 - * - * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 will be - */ - if((tm->tm_year%4==0) && - ((tm->tm_year%100!=0) || (tm->tm_year%400==0)) && - (tm->tm_mon>2)) - { - /* - * We are past Feb. 29 in a leap year - */ - day=1; - } - else - { - day=0; - } - - day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + - tm->tm_mday; - - tm->tm_wday=day%7; -} - -void to_tm(int tim, struct rtc_time * tm) -{ - register int i; - register long hms, day; - - day = tim / SECDAY; - hms = tim % SECDAY; - - /* Hours, minutes, seconds are easy */ - tm->tm_hour = hms / 3600; - tm->tm_min = (hms % 3600) / 60; - tm->tm_sec = (hms % 3600) % 60; - - /* Number of years in days */ - for (i = STARTOFTIME; day >= days_in_year(i); i++) - day -= days_in_year(i); - tm->tm_year = i; - - /* Number of months in days left */ - if (leapyear(tm->tm_year)) - days_in_month(FEBRUARY) = 29; - for (i = 1; day >= days_in_month(i); i++) - day -= days_in_month(i); - days_in_month(FEBRUARY) = 28; - tm->tm_mon = i; - - /* Days are what is left over (+1) from all that. */ - tm->tm_mday = day + 1; - - /* - * Determine the day of week - */ - GregorianDay(tm); -} - -/* Auxiliary function to compute scaling factors */ -/* Actually the choice of a timebase running at 1/4 the of the bus - * frequency giving resolution of a few tens of nanoseconds is quite nice. - * It makes this computation very precise (27-28 bits typically) which - * is optimistic considering the stability of most processor clock - * oscillators and the precision with which the timebase frequency - * is measured but does not harm. - */ -unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) { - unsigned mlt=0, tmp, err; - /* No concern for performance, it's done once: use a stupid - * but safe and compact method to find the multiplier. - */ - - for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { - if (mulhwu(inscale, mlt|tmp) < outscale) mlt|=tmp; - } - - /* We might still be off by 1 for the best approximation. - * A side effect of this is that if outscale is too large - * the returned value will be zero. - * Many corner cases have been checked and seem to work, - * some might have been forgotten in the test however. - */ - - err = inscale*(mlt+1); - if (err <= inscale/2) mlt++; - return mlt; - } - -/* - * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit - * result. - */ - -void div128_by_32( unsigned long dividend_high, unsigned long dividend_low, - unsigned divisor, struct div_result *dr ) -{ - unsigned long a,b,c,d, w,x,y,z, ra,rb,rc; - - a = dividend_high >> 32; - b = dividend_high & 0xffffffff; - c = dividend_low >> 32; - d = dividend_low & 0xffffffff; - - w = a/divisor; - ra = (a - (w * divisor)) << 32; - - x = (ra + b)/divisor; - rb = ((ra + b) - (x * divisor)) << 32; - - y = (rb + c)/divisor; - rc = ((rb + b) - (y * divisor)) << 32; - - z = (rc + d)/divisor; - - dr->result_high = (w << 32) + x; - dr->result_low = (y << 32) + z; - -} - |
