| /* |
| * 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/errno.h> |
| #include <linux/module.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/param.h> |
| #include <linux/string.h> |
| #include <linux/mm.h> |
| #include <linux/interrupt.h> |
| #include <linux/timex.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/time.h> |
| #include <linux/init.h> |
| #include <linux/profile.h> |
| #include <linux/cpu.h> |
| #include <linux/security.h> |
| #include <linux/percpu.h> |
| #include <linux/rtc.h> |
| #include <linux/jiffies.h> |
| #include <linux/posix-timers.h> |
| #include <linux/irq.h> |
| |
| #include <asm/io.h> |
| #include <asm/processor.h> |
| #include <asm/nvram.h> |
| #include <asm/cache.h> |
| #include <asm/machdep.h> |
| #include <asm/uaccess.h> |
| #include <asm/time.h> |
| #include <asm/prom.h> |
| #include <asm/irq.h> |
| #include <asm/div64.h> |
| #include <asm/smp.h> |
| #include <asm/vdso_datapage.h> |
| #include <asm/firmware.h> |
| #include <asm/cputime.h> |
| #ifdef CONFIG_PPC_ISERIES |
| #include <asm/iseries/it_lp_queue.h> |
| #include <asm/iseries/hv_call_xm.h> |
| #endif |
| |
| /* powerpc clocksource/clockevent code */ |
| |
| #include <linux/clockchips.h> |
| #include <linux/clocksource.h> |
| |
| static cycle_t rtc_read(struct clocksource *); |
| static struct clocksource clocksource_rtc = { |
| .name = "rtc", |
| .rating = 400, |
| .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| .mask = CLOCKSOURCE_MASK(64), |
| .shift = 22, |
| .mult = 0, /* To be filled in */ |
| .read = rtc_read, |
| }; |
| |
| static cycle_t timebase_read(struct clocksource *); |
| static struct clocksource clocksource_timebase = { |
| .name = "timebase", |
| .rating = 400, |
| .flags = CLOCK_SOURCE_IS_CONTINUOUS, |
| .mask = CLOCKSOURCE_MASK(64), |
| .shift = 22, |
| .mult = 0, /* To be filled in */ |
| .read = timebase_read, |
| }; |
| |
| #define DECREMENTER_MAX 0x7fffffff |
| |
| static int decrementer_set_next_event(unsigned long evt, |
| struct clock_event_device *dev); |
| static void decrementer_set_mode(enum clock_event_mode mode, |
| struct clock_event_device *dev); |
| |
| static struct clock_event_device decrementer_clockevent = { |
| .name = "decrementer", |
| .rating = 200, |
| .shift = 0, /* To be filled in */ |
| .mult = 0, /* To be filled in */ |
| .irq = 0, |
| .set_next_event = decrementer_set_next_event, |
| .set_mode = decrementer_set_mode, |
| .features = CLOCK_EVT_FEAT_ONESHOT, |
| }; |
| |
| struct decrementer_clock { |
| struct clock_event_device event; |
| u64 next_tb; |
| }; |
| |
| static DEFINE_PER_CPU(struct decrementer_clock, decrementers); |
| |
| #ifdef CONFIG_PPC_ISERIES |
| static unsigned long __initdata iSeries_recal_titan; |
| static signed long __initdata iSeries_recal_tb; |
| |
| /* Forward declaration is only needed for iSereis compiles */ |
| static void __init clocksource_init(void); |
| #endif |
| |
| #define XSEC_PER_SEC (1024*1024) |
| |
| #ifdef CONFIG_PPC64 |
| #define SCALE_XSEC(xsec, max) (((xsec) * max) / XSEC_PER_SEC) |
| #else |
| /* compute ((xsec << 12) * max) >> 32 */ |
| #define SCALE_XSEC(xsec, max) mulhwu((xsec) << 12, max) |
| #endif |
| |
| unsigned long tb_ticks_per_jiffy; |
| unsigned long tb_ticks_per_usec = 100; /* sane default */ |
| EXPORT_SYMBOL(tb_ticks_per_usec); |
| unsigned long tb_ticks_per_sec; |
| EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ |
| u64 tb_to_xs; |
| unsigned tb_to_us; |
| |
| #define TICKLEN_SCALE NTP_SCALE_SHIFT |
| static u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ |
| static u64 ticklen_to_xs; /* 0.64 fraction */ |
| |
| /* If last_tick_len corresponds to about 1/HZ seconds, then |
| last_tick_len << TICKLEN_SHIFT will be about 2^63. */ |
| #define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ) |
| |
| DEFINE_SPINLOCK(rtc_lock); |
| EXPORT_SYMBOL_GPL(rtc_lock); |
| |
| static u64 tb_to_ns_scale __read_mostly; |
| static unsigned tb_to_ns_shift __read_mostly; |
| static unsigned long boot_tb __read_mostly; |
| |
| extern struct timezone sys_tz; |
| static long timezone_offset; |
| |
| unsigned long ppc_proc_freq; |
| EXPORT_SYMBOL(ppc_proc_freq); |
| unsigned long ppc_tb_freq; |
| |
| static u64 tb_last_jiffy __cacheline_aligned_in_smp; |
| static DEFINE_PER_CPU(u64, last_jiffy); |
| |
| #ifdef CONFIG_VIRT_CPU_ACCOUNTING |
| /* |
| * Factors for converting from cputime_t (timebase ticks) to |
| * jiffies, milliseconds, seconds, and clock_t (1/USER_HZ seconds). |
| * These are all stored as 0.64 fixed-point binary fractions. |
| */ |
| u64 __cputime_jiffies_factor; |
| EXPORT_SYMBOL(__cputime_jiffies_factor); |
| u64 __cputime_msec_factor; |
| EXPORT_SYMBOL(__cputime_msec_factor); |
| u64 __cputime_sec_factor; |
| EXPORT_SYMBOL(__cputime_sec_factor); |
| u64 __cputime_clockt_factor; |
| EXPORT_SYMBOL(__cputime_clockt_factor); |
| DEFINE_PER_CPU(unsigned long, cputime_last_delta); |
| DEFINE_PER_CPU(unsigned long, cputime_scaled_last_delta); |
| |
| static void calc_cputime_factors(void) |
| { |
| struct div_result res; |
| |
| div128_by_32(HZ, 0, tb_ticks_per_sec, &res); |
| __cputime_jiffies_factor = res.result_low; |
| div128_by_32(1000, 0, tb_ticks_per_sec, &res); |
| __cputime_msec_factor = res.result_low; |
| div128_by_32(1, 0, tb_ticks_per_sec, &res); |
| __cputime_sec_factor = res.result_low; |
| div128_by_32(USER_HZ, 0, tb_ticks_per_sec, &res); |
| __cputime_clockt_factor = res.result_low; |
| } |
| |
| /* |
| * Read the PURR on systems that have it, otherwise the timebase. |
| */ |
| static u64 read_purr(void) |
| { |
| if (cpu_has_feature(CPU_FTR_PURR)) |
| return mfspr(SPRN_PURR); |
| return mftb(); |
| } |
| |
| /* |
| * Read the SPURR on systems that have it, otherwise the purr |
| */ |
| static u64 read_spurr(u64 purr) |
| { |
| /* |
| * cpus without PURR won't have a SPURR |
| * We already know the former when we use this, so tell gcc |
| */ |
| if (cpu_has_feature(CPU_FTR_PURR) && cpu_has_feature(CPU_FTR_SPURR)) |
| return mfspr(SPRN_SPURR); |
| return purr; |
| } |
| |
| /* |
| * Account time for a transition between system, hard irq |
| * or soft irq state. |
| */ |
| void account_system_vtime(struct task_struct *tsk) |
| { |
| u64 now, nowscaled, delta, deltascaled, sys_time; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| now = read_purr(); |
| nowscaled = read_spurr(now); |
| delta = now - get_paca()->startpurr; |
| deltascaled = nowscaled - get_paca()->startspurr; |
| get_paca()->startpurr = now; |
| get_paca()->startspurr = nowscaled; |
| if (!in_interrupt()) { |
| /* deltascaled includes both user and system time. |
| * Hence scale it based on the purr ratio to estimate |
| * the system time */ |
| sys_time = get_paca()->system_time; |
| if (get_paca()->user_time) |
| deltascaled = deltascaled * sys_time / |
| (sys_time + get_paca()->user_time); |
| delta += sys_time; |
| get_paca()->system_time = 0; |
| } |
| if (in_irq() || idle_task(smp_processor_id()) != tsk) |
| account_system_time(tsk, 0, delta, deltascaled); |
| else |
| account_idle_time(delta); |
| per_cpu(cputime_last_delta, smp_processor_id()) = delta; |
| per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled; |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Transfer the user and system times accumulated in the paca |
| * by the exception entry and exit code to the generic process |
| * user and system time records. |
| * Must be called with interrupts disabled. |
| */ |
| void account_process_tick(struct task_struct *tsk, int user_tick) |
| { |
| cputime_t utime, utimescaled; |
| |
| utime = get_paca()->user_time; |
| get_paca()->user_time = 0; |
| utimescaled = cputime_to_scaled(utime); |
| account_user_time(tsk, utime, utimescaled); |
| } |
| |
| /* |
| * Stuff for accounting stolen time. |
| */ |
| struct cpu_purr_data { |
| int initialized; /* thread is running */ |
| u64 tb; /* last TB value read */ |
| u64 purr; /* last PURR value read */ |
| u64 spurr; /* last SPURR value read */ |
| }; |
| |
| /* |
| * Each entry in the cpu_purr_data array is manipulated only by its |
| * "owner" cpu -- usually in the timer interrupt but also occasionally |
| * in process context for cpu online. As long as cpus do not touch |
| * each others' cpu_purr_data, disabling local interrupts is |
| * sufficient to serialize accesses. |
| */ |
| static DEFINE_PER_CPU(struct cpu_purr_data, cpu_purr_data); |
| |
| static void snapshot_tb_and_purr(void *data) |
| { |
| unsigned long flags; |
| struct cpu_purr_data *p = &__get_cpu_var(cpu_purr_data); |
| |
| local_irq_save(flags); |
| p->tb = get_tb_or_rtc(); |
| p->purr = mfspr(SPRN_PURR); |
| wmb(); |
| p->initialized = 1; |
| local_irq_restore(flags); |
| } |
| |
| /* |
| * Called during boot when all cpus have come up. |
| */ |
| void snapshot_timebases(void) |
| { |
| if (!cpu_has_feature(CPU_FTR_PURR)) |
| return; |
| on_each_cpu(snapshot_tb_and_purr, NULL, 1); |
| } |
| |
| /* |
| * Must be called with interrupts disabled. |
| */ |
| void calculate_steal_time(void) |
| { |
| u64 tb, purr; |
| s64 stolen; |
| struct cpu_purr_data *pme; |
| |
| pme = &__get_cpu_var(cpu_purr_data); |
| if (!pme->initialized) |
| return; /* !CPU_FTR_PURR or early in early boot */ |
| tb = mftb(); |
| purr = mfspr(SPRN_PURR); |
| stolen = (tb - pme->tb) - (purr - pme->purr); |
| if (stolen > 0) { |
| if (idle_task(smp_processor_id()) != current) |
| account_steal_time(stolen); |
| else |
| account_idle_time(stolen); |
| } |
| pme->tb = tb; |
| pme->purr = purr; |
| } |
| |
| #ifdef CONFIG_PPC_SPLPAR |
| /* |
| * Must be called before the cpu is added to the online map when |
| * a cpu is being brought up at runtime. |
| */ |
| static void snapshot_purr(void) |
| { |
| struct cpu_purr_data *pme; |
| unsigned long flags; |
| |
| if (!cpu_has_feature(CPU_FTR_PURR)) |
| return; |
| local_irq_save(flags); |
| pme = &__get_cpu_var(cpu_purr_data); |
| pme->tb = mftb(); |
| pme->purr = mfspr(SPRN_PURR); |
| pme->initialized = 1; |
| local_irq_restore(flags); |
| } |
| |
| #endif /* CONFIG_PPC_SPLPAR */ |
| |
| #else /* ! CONFIG_VIRT_CPU_ACCOUNTING */ |
| #define calc_cputime_factors() |
| #define calculate_steal_time() do { } while (0) |
| #endif |
| |
| #if !(defined(CONFIG_VIRT_CPU_ACCOUNTING) && defined(CONFIG_PPC_SPLPAR)) |
| #define snapshot_purr() do { } while (0) |
| #endif |
| |
| /* |
| * Called when a cpu comes up after the system has finished booting, |
| * i.e. as a result of a hotplug cpu action. |
| */ |
| void snapshot_timebase(void) |
| { |
| __get_cpu_var(last_jiffy) = get_tb_or_rtc(); |
| snapshot_purr(); |
| } |
| |
| void __delay(unsigned long loops) |
| { |
| unsigned long start; |
| int diff; |
| |
| if (__USE_RTC()) { |
| start = get_rtcl(); |
| do { |
| /* the RTCL register wraps at 1000000000 */ |
| diff = get_rtcl() - start; |
| if (diff < 0) |
| diff += 1000000000; |
| } while (diff < loops); |
| } else { |
| start = get_tbl(); |
| while (get_tbl() - start < loops) |
| HMT_low(); |
| HMT_medium(); |
| } |
| } |
| EXPORT_SYMBOL(__delay); |
| |
| void udelay(unsigned long usecs) |
| { |
| __delay(tb_ticks_per_usec * usecs); |
| } |
| EXPORT_SYMBOL(udelay); |
| |
| static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, |
| u64 new_tb_to_xs) |
| { |
| /* |
| * tb_update_count is used to allow the userspace gettimeofday code |
| * to assure itself that it sees a consistent view of the tb_to_xs and |
| * stamp_xsec variables. It reads the tb_update_count, then reads |
| * tb_to_xs and stamp_xsec and then reads tb_update_count again. If |
| * the two values of tb_update_count match and are even then the |
| * tb_to_xs and stamp_xsec values are consistent. If not, then it |
| * loops back and reads them again until this criteria is met. |
| * We expect the caller to have done the first increment of |
| * vdso_data->tb_update_count already. |
| */ |
| vdso_data->tb_orig_stamp = new_tb_stamp; |
| vdso_data->stamp_xsec = new_stamp_xsec; |
| vdso_data->tb_to_xs = new_tb_to_xs; |
| vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; |
| vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; |
| vdso_data->stamp_xtime = xtime; |
| smp_wmb(); |
| ++(vdso_data->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 int __init iSeries_tb_recal(void) |
| { |
| struct div_result divres; |
| unsigned long titan, tb; |
| |
| /* Make sure we only run on iSeries */ |
| if (!firmware_has_feature(FW_FEATURE_ISERIES)) |
| return -ENODEV; |
| |
| tb = get_tb(); |
| titan = HvCallXm_loadTod(); |
| if ( iSeries_recal_titan ) { |
| unsigned long tb_ticks = tb - iSeries_recal_tb; |
| unsigned long titan_usec = (titan - iSeries_recal_titan) >> 12; |
| unsigned long new_tb_ticks_per_sec = (tb_ticks * USEC_PER_SEC)/titan_usec; |
| unsigned long new_tb_ticks_per_jiffy = (new_tb_ticks_per_sec+(HZ/2))/HZ; |
| long tick_diff = new_tb_ticks_per_jiffy - tb_ticks_per_jiffy; |
| char sign = '+'; |
| /* make sure tb_ticks_per_sec and tb_ticks_per_jiffy are consistent */ |
| new_tb_ticks_per_sec = new_tb_ticks_per_jiffy * HZ; |
| |
| if ( tick_diff < 0 ) { |
| tick_diff = -tick_diff; |
| sign = '-'; |
| } |
| if ( tick_diff ) { |
| if ( tick_diff < tb_ticks_per_jiffy/25 ) { |
| printk( "Titan recalibrate: new tb_ticks_per_jiffy = %lu (%c%ld)\n", |
| new_tb_ticks_per_jiffy, sign, tick_diff ); |
| tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; |
| tb_ticks_per_sec = new_tb_ticks_per_sec; |
| calc_cputime_factors(); |
| div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); |
| tb_to_xs = divres.result_low; |
| vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
| vdso_data->tb_to_xs = tb_to_xs; |
| } |
| else { |
| printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" |
| " new tb_ticks_per_jiffy = %lu\n" |
| " old tb_ticks_per_jiffy = %lu\n", |
| new_tb_ticks_per_jiffy, tb_ticks_per_jiffy ); |
| } |
| } |
| } |
| iSeries_recal_titan = titan; |
| iSeries_recal_tb = tb; |
| |
| /* Called here as now we know accurate values for the timebase */ |
| clocksource_init(); |
| return 0; |
| } |
| late_initcall(iSeries_tb_recal); |
| |
| /* Called from platform early init */ |
| void __init iSeries_time_init_early(void) |
| { |
| iSeries_recal_tb = get_tb(); |
| iSeries_recal_titan = HvCallXm_loadTod(); |
| } |
| #endif /* CONFIG_PPC_ISERIES */ |
| |
| /* |
| * For iSeries shared processors, we have to let the hypervisor |
| * set the hardware decrementer. We set a virtual decrementer |
| * in the lppaca and call the hypervisor if the virtual |
| * decrementer is less than the current value in the hardware |
| * decrementer. (almost always the new decrementer value will |
| * be greater than the current hardware decementer so the hypervisor |
| * call will not be needed) |
| */ |
| |
| /* |
| * timer_interrupt - gets called when the decrementer overflows, |
| * with interrupts disabled. |
| */ |
| void timer_interrupt(struct pt_regs * regs) |
| { |
| struct pt_regs *old_regs; |
| struct decrementer_clock *decrementer = &__get_cpu_var(decrementers); |
| struct clock_event_device *evt = &decrementer->event; |
| u64 now; |
| |
| /* Ensure a positive value is written to the decrementer, or else |
| * some CPUs will continuue to take decrementer exceptions */ |
| set_dec(DECREMENTER_MAX); |
| |
| #ifdef CONFIG_PPC32 |
| if (atomic_read(&ppc_n_lost_interrupts) != 0) |
| do_IRQ(regs); |
| #endif |
| |
| now = get_tb_or_rtc(); |
| if (now < decrementer->next_tb) { |
| /* not time for this event yet */ |
| now = decrementer->next_tb - now; |
| if (now <= DECREMENTER_MAX) |
| set_dec((int)now); |
| return; |
| } |
| old_regs = set_irq_regs(regs); |
| irq_enter(); |
| |
| calculate_steal_time(); |
| |
| #ifdef CONFIG_PPC_ISERIES |
| if (firmware_has_feature(FW_FEATURE_ISERIES)) |
| get_lppaca()->int_dword.fields.decr_int = 0; |
| #endif |
| |
| if (evt->event_handler) |
| evt->event_handler(evt); |
| |
| #ifdef CONFIG_PPC_ISERIES |
| if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending()) |
| process_hvlpevents(); |
| #endif |
| |
| #ifdef CONFIG_PPC64 |
| /* collect purr register values often, for accurate calculations */ |
| if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
| struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array); |
| cu->current_tb = mfspr(SPRN_PURR); |
| } |
| #endif |
| |
| irq_exit(); |
| set_irq_regs(old_regs); |
| } |
| |
| void wakeup_decrementer(void) |
| { |
| unsigned long ticks; |
| |
| /* |
| * The timebase gets saved on sleep and restored on wakeup, |
| * so all we need to do is to reset the decrementer. |
| */ |
| ticks = tb_ticks_since(__get_cpu_var(last_jiffy)); |
| if (ticks < tb_ticks_per_jiffy) |
| ticks = tb_ticks_per_jiffy - ticks; |
| else |
| ticks = 1; |
| set_dec(ticks); |
| } |
| |
| #ifdef CONFIG_SUSPEND |
| void generic_suspend_disable_irqs(void) |
| { |
| preempt_disable(); |
| |
| /* Disable the decrementer, so that it doesn't interfere |
| * with suspending. |
| */ |
| |
| set_dec(0x7fffffff); |
| local_irq_disable(); |
| set_dec(0x7fffffff); |
| } |
| |
| void generic_suspend_enable_irqs(void) |
| { |
| wakeup_decrementer(); |
| |
| local_irq_enable(); |
| preempt_enable(); |
| } |
| |
| /* Overrides the weak version in kernel/power/main.c */ |
| void arch_suspend_disable_irqs(void) |
| { |
| if (ppc_md.suspend_disable_irqs) |
| ppc_md.suspend_disable_irqs(); |
| generic_suspend_disable_irqs(); |
| } |
| |
| /* Overrides the weak version in kernel/power/main.c */ |
| void arch_suspend_enable_irqs(void) |
| { |
| generic_suspend_enable_irqs(); |
| if (ppc_md.suspend_enable_irqs) |
| ppc_md.suspend_enable_irqs(); |
| } |
| #endif |
| |
| #ifdef CONFIG_SMP |
| void __init smp_space_timers(unsigned int max_cpus) |
| { |
| int i; |
| u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); |
| |
| /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ |
| previous_tb -= tb_ticks_per_jiffy; |
| |
| for_each_possible_cpu(i) { |
| if (i == boot_cpuid) |
| continue; |
| per_cpu(last_jiffy, i) = previous_tb; |
| } |
| } |
| #endif |
| |
| /* |
| * Scheduler clock - returns current time in nanosec units. |
| * |
| * Note: mulhdu(a, b) (multiply high double unsigned) returns |
| * the high 64 bits of a * b, i.e. (a * b) >> 64, where a and b |
| * are 64-bit unsigned numbers. |
| */ |
| unsigned long long sched_clock(void) |
| { |
| if (__USE_RTC()) |
| return get_rtc(); |
| return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; |
| } |
| |
| static int __init get_freq(char *name, int cells, unsigned long *val) |
| { |
| struct device_node *cpu; |
| const unsigned int *fp; |
| int found = 0; |
| |
| /* The cpu node should have timebase and clock frequency properties */ |
| cpu = of_find_node_by_type(NULL, "cpu"); |
| |
| if (cpu) { |
| fp = of_get_property(cpu, name, NULL); |
| if (fp) { |
| found = 1; |
| *val = of_read_ulong(fp, cells); |
| } |
| |
| of_node_put(cpu); |
| } |
| |
| return found; |
| } |
| |
| void __init generic_calibrate_decr(void) |
| { |
| ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ |
| |
| if (!get_freq("ibm,extended-timebase-frequency", 2, &ppc_tb_freq) && |
| !get_freq("timebase-frequency", 1, &ppc_tb_freq)) { |
| |
| printk(KERN_ERR "WARNING: Estimating decrementer frequency " |
| "(not found)\n"); |
| } |
| |
| ppc_proc_freq = DEFAULT_PROC_FREQ; /* hardcoded default */ |
| |
| if (!get_freq("ibm,extended-clock-frequency", 2, &ppc_proc_freq) && |
| !get_freq("clock-frequency", 1, &ppc_proc_freq)) { |
| |
| printk(KERN_ERR "WARNING: Estimating processor frequency " |
| "(not found)\n"); |
| } |
| |
| #if defined(CONFIG_BOOKE) || defined(CONFIG_40x) |
| /* Clear any pending timer interrupts */ |
| mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); |
| |
| /* Enable decrementer interrupt */ |
| mtspr(SPRN_TCR, TCR_DIE); |
| #endif |
| } |
| |
| int update_persistent_clock(struct timespec now) |
| { |
| struct rtc_time tm; |
| |
| if (!ppc_md.set_rtc_time) |
| return 0; |
| |
| to_tm(now.tv_sec + 1 + timezone_offset, &tm); |
| tm.tm_year -= 1900; |
| tm.tm_mon -= 1; |
| |
| return ppc_md.set_rtc_time(&tm); |
| } |
| |
| unsigned long read_persistent_clock(void) |
| { |
| struct rtc_time tm; |
| static int first = 1; |
| |
| /* XXX this is a litle fragile but will work okay in the short term */ |
| if (first) { |
| first = 0; |
| if (ppc_md.time_init) |
| timezone_offset = ppc_md.time_init(); |
| |
| /* get_boot_time() isn't guaranteed to be safe to call late */ |
| if (ppc_md.get_boot_time) |
| return ppc_md.get_boot_time() -timezone_offset; |
| } |
| 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); |
| } |
| |
| /* clocksource code */ |
| static cycle_t rtc_read(struct clocksource *cs) |
| { |
| return (cycle_t)get_rtc(); |
| } |
| |
| static cycle_t timebase_read(struct clocksource *cs) |
| { |
| return (cycle_t)get_tb(); |
| } |
| |
| void update_vsyscall(struct timespec *wall_time, struct clocksource *clock) |
| { |
| u64 t2x, stamp_xsec; |
| |
| if (clock != &clocksource_timebase) |
| return; |
| |
| /* Make userspace gettimeofday spin until we're done. */ |
| ++vdso_data->tb_update_count; |
| smp_mb(); |
| |
| /* XXX this assumes clock->shift == 22 */ |
| /* 4611686018 ~= 2^(20+64-22) / 1e9 */ |
| t2x = (u64) clock->mult * 4611686018ULL; |
| stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; |
| do_div(stamp_xsec, 1000000000); |
| stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; |
| update_gtod(clock->cycle_last, stamp_xsec, t2x); |
| } |
| |
| void update_vsyscall_tz(void) |
| { |
| /* Make userspace gettimeofday spin until we're done. */ |
| ++vdso_data->tb_update_count; |
| smp_mb(); |
| vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; |
| vdso_data->tz_dsttime = sys_tz.tz_dsttime; |
| smp_mb(); |
| ++vdso_data->tb_update_count; |
| } |
| |
| static void __init clocksource_init(void) |
| { |
| struct clocksource *clock; |
| |
| if (__USE_RTC()) |
| clock = &clocksource_rtc; |
| else |
| clock = &clocksource_timebase; |
| |
| clock->mult = clocksource_hz2mult(tb_ticks_per_sec, clock->shift); |
| |
| if (clocksource_register(clock)) { |
| printk(KERN_ERR "clocksource: %s is already registered\n", |
| clock->name); |
| return; |
| } |
| |
| printk(KERN_INFO "clocksource: %s mult[%x] shift[%d] registered\n", |
| clock->name, clock->mult, clock->shift); |
| } |
| |
| static int decrementer_set_next_event(unsigned long evt, |
| struct clock_event_device *dev) |
| { |
| __get_cpu_var(decrementers).next_tb = get_tb_or_rtc() + evt; |
| set_dec(evt); |
| return 0; |
| } |
| |
| static void decrementer_set_mode(enum clock_event_mode mode, |
| struct clock_event_device *dev) |
| { |
| if (mode != CLOCK_EVT_MODE_ONESHOT) |
| decrementer_set_next_event(DECREMENTER_MAX, dev); |
| } |
| |
| static void __init setup_clockevent_multiplier(unsigned long hz) |
| { |
| u64 mult, shift = 32; |
| |
| while (1) { |
| mult = div_sc(hz, NSEC_PER_SEC, shift); |
| if (mult && (mult >> 32UL) == 0UL) |
| break; |
| |
| shift--; |
| } |
| |
| decrementer_clockevent.shift = shift; |
| decrementer_clockevent.mult = mult; |
| } |
| |
| static void register_decrementer_clockevent(int cpu) |
| { |
| struct clock_event_device *dec = &per_cpu(decrementers, cpu).event; |
| |
| *dec = decrementer_clockevent; |
| dec->cpumask = cpumask_of(cpu); |
| |
| printk(KERN_DEBUG "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n", |
| dec->name, dec->mult, dec->shift, cpu); |
| |
| clockevents_register_device(dec); |
| } |
| |
| static void __init init_decrementer_clockevent(void) |
| { |
| int cpu = smp_processor_id(); |
| |
| setup_clockevent_multiplier(ppc_tb_freq); |
| decrementer_clockevent.max_delta_ns = |
| clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent); |
| decrementer_clockevent.min_delta_ns = |
| clockevent_delta2ns(2, &decrementer_clockevent); |
| |
| register_decrementer_clockevent(cpu); |
| } |
| |
| void secondary_cpu_time_init(void) |
| { |
| /* FIME: Should make unrelatred change to move snapshot_timebase |
| * call here ! */ |
| register_decrementer_clockevent(smp_processor_id()); |
| } |
| |
| /* This function is only called on the boot processor */ |
| void __init time_init(void) |
| { |
| unsigned long flags; |
| struct div_result res; |
| u64 scale, x; |
| unsigned shift; |
| |
| if (__USE_RTC()) { |
| /* 601 processor: dec counts down by 128 every 128ns */ |
| ppc_tb_freq = 1000000000; |
| tb_last_jiffy = get_rtcl(); |
| } else { |
| /* Normal PowerPC with timebase register */ |
| ppc_md.calibrate_decr(); |
| printk(KERN_DEBUG "time_init: decrementer frequency = %lu.%.6lu MHz\n", |
| ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); |
| printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", |
| ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); |
| tb_last_jiffy = get_tb(); |
| } |
| |
| tb_ticks_per_jiffy = ppc_tb_freq / HZ; |
| tb_ticks_per_sec = ppc_tb_freq; |
| tb_ticks_per_usec = ppc_tb_freq / 1000000; |
| tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000); |
| calc_cputime_factors(); |
| |
| /* |
| * Calculate the length of each tick in ns. It will not be |
| * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ. |
| * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq, |
| * rounded up. |
| */ |
| x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1; |
| do_div(x, ppc_tb_freq); |
| tick_nsec = x; |
| last_tick_len = x << TICKLEN_SCALE; |
| |
| /* |
| * Compute ticklen_to_xs, which is a factor which gets multiplied |
| * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value. |
| * It is computed as: |
| * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) |
| * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT |
| * which turns out to be N = 51 - SHIFT_HZ. |
| * This gives the result as a 0.64 fixed-point fraction. |
| * That value is reduced by an offset amounting to 1 xsec per |
| * 2^31 timebase ticks to avoid problems with time going backwards |
| * by 1 xsec when we do timer_recalc_offset due to losing the |
| * fractional xsec. That offset is equal to ppc_tb_freq/2^51 |
| * since there are 2^20 xsec in a second. |
| */ |
| div128_by_32((1ULL << 51) - ppc_tb_freq, 0, |
| tb_ticks_per_jiffy << SHIFT_HZ, &res); |
| div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); |
| ticklen_to_xs = res.result_low; |
| |
| /* Compute tb_to_xs from tick_nsec */ |
| tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs); |
| |
| /* |
| * Compute scale factor for sched_clock. |
| * The calibrate_decr() function has set tb_ticks_per_sec, |
| * which is the timebase frequency. |
| * We compute 1e9 * 2^64 / tb_ticks_per_sec and interpret |
| * the 128-bit result as a 64.64 fixed-point number. |
| * We then shift that number right until it is less than 1.0, |
| * giving us the scale factor and shift count to use in |
| * sched_clock(). |
| */ |
| div128_by_32(1000000000, 0, tb_ticks_per_sec, &res); |
| scale = res.result_low; |
| for (shift = 0; res.result_high != 0; ++shift) { |
| scale = (scale >> 1) | (res.result_high << 63); |
| res.result_high >>= 1; |
| } |
| tb_to_ns_scale = scale; |
| tb_to_ns_shift = shift; |
| /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ |
| boot_tb = get_tb_or_rtc(); |
| |
| write_seqlock_irqsave(&xtime_lock, flags); |
| |
| /* If platform provided a timezone (pmac), we correct the time */ |
| if (timezone_offset) { |
| sys_tz.tz_minuteswest = -timezone_offset / 60; |
| sys_tz.tz_dsttime = 0; |
| } |
| |
| vdso_data->tb_orig_stamp = tb_last_jiffy; |
| vdso_data->tb_update_count = 0; |
| vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; |
| vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; |
| vdso_data->tb_to_xs = tb_to_xs; |
| |
| write_sequnlock_irqrestore(&xtime_lock, flags); |
| |
| /* Register the clocksource, if we're not running on iSeries */ |
| if (!firmware_has_feature(FW_FEATURE_ISERIES)) |
| clocksource_init(); |
| |
| init_decrementer_clockevent(); |
| } |
| |
| |
| #define FEBRUARY 2 |
| #define STARTOFTIME 1970 |
| #define SECDAY 86400L |
| #define SECYR (SECDAY * 365) |
| #define leapyear(year) ((year) % 4 == 0 && \ |
| ((year) % 100 != 0 || (year) % 400 == 0)) |
| #define days_in_year(a) (leapyear(a) ? 366 : 365) |
| #define days_in_month(a) (month_days[(a) - 1]) |
| |
| static int month_days[12] = { |
| 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 |
| }; |
| |
| /* |
| * This only works for the Gregorian calendar - i.e. after 1752 (in the UK) |
| */ |
| void GregorianDay(struct rtc_time * tm) |
| { |
| int leapsToDate; |
| int lastYear; |
| int day; |
| int MonthOffset[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; |
| |
| lastYear = tm->tm_year - 1; |
| |
| /* |
| * Number of leap corrections to apply up to end of last year |
| */ |
| leapsToDate = lastYear / 4 - lastYear / 100 + lastYear / 400; |
| |
| /* |
| * This year is a leap year if it is divisible by 4 except when it is |
| * divisible by 100 unless it is divisible by 400 |
| * |
| * e.g. 1904 was a leap year, 1900 was not, 1996 is, and 2000 was |
| */ |
| day = tm->tm_mon > 2 && leapyear(tm->tm_year); |
| |
| day += lastYear*365 + leapsToDate + MonthOffset[tm->tm_mon-1] + |
| tm->tm_mday; |
| |
| tm->tm_wday = day % 7; |
| } |
| |
| void to_tm(int tim, struct rtc_time * tm) |
| { |
| register int i; |
| register long hms, day; |
| |
| day = tim / SECDAY; |
| hms = tim % SECDAY; |
| |
| /* Hours, minutes, seconds are easy */ |
| tm->tm_hour = hms / 3600; |
| tm->tm_min = (hms % 3600) / 60; |
| tm->tm_sec = (hms % 3600) % 60; |
| |
| /* Number of years in days */ |
| for (i = STARTOFTIME; day >= days_in_year(i); i++) |
| day -= days_in_year(i); |
| tm->tm_year = i; |
| |
| /* Number of months in days left */ |
| if (leapyear(tm->tm_year)) |
| days_in_month(FEBRUARY) = 29; |
| for (i = 1; day >= days_in_month(i); i++) |
| day -= days_in_month(i); |
| days_in_month(FEBRUARY) = 28; |
| tm->tm_mon = i; |
| |
| /* Days are what is left over (+1) from all that. */ |
| tm->tm_mday = day + 1; |
| |
| /* |
| * Determine the day of week |
| */ |
| GregorianDay(tm); |
| } |
| |
| /* Auxiliary function to compute scaling factors */ |
| /* Actually the choice of a timebase running at 1/4 the of the bus |
| * frequency giving resolution of a few tens of nanoseconds is quite nice. |
| * It makes this computation very precise (27-28 bits typically) which |
| * is optimistic considering the stability of most processor clock |
| * oscillators and the precision with which the timebase frequency |
| * is measured but does not harm. |
| */ |
| unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) |
| { |
| unsigned mlt=0, tmp, err; |
| /* No concern for performance, it's done once: use a stupid |
| * but safe and compact method to find the multiplier. |
| */ |
| |
| for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { |
| if (mulhwu(inscale, mlt|tmp) < outscale) |
| mlt |= tmp; |
| } |
| |
| /* We might still be off by 1 for the best approximation. |
| * A side effect of this is that if outscale is too large |
| * the returned value will be zero. |
| * Many corner cases have been checked and seem to work, |
| * some might have been forgotten in the test however. |
| */ |
| |
| err = inscale * (mlt+1); |
| if (err <= inscale/2) |
| mlt++; |
| return mlt; |
| } |
| |
| /* |
| * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit |
| * result. |
| */ |
| void div128_by_32(u64 dividend_high, u64 dividend_low, |
| unsigned divisor, struct div_result *dr) |
| { |
| unsigned long a, b, c, d; |
| unsigned long w, x, y, z; |
| u64 ra, rb, rc; |
| |
| a = dividend_high >> 32; |
| b = dividend_high & 0xffffffff; |
| c = dividend_low >> 32; |
| d = dividend_low & 0xffffffff; |
| |
| w = a / divisor; |
| ra = ((u64)(a - (w * divisor)) << 32) + b; |
| |
| rb = ((u64) do_div(ra, divisor) << 32) + c; |
| x = ra; |
| |
| rc = ((u64) do_div(rb, divisor) << 32) + d; |
| y = rb; |
| |
| do_div(rc, divisor); |
| z = rc; |
| |
| dr->result_high = ((u64)w << 32) + x; |
| dr->result_low = ((u64)y << 32) + z; |
| |
| } |
| |
| static int __init rtc_init(void) |
| { |
| struct platform_device *pdev; |
| |
| if (!ppc_md.get_rtc_time) |
| return -ENODEV; |
| |
| pdev = platform_device_register_simple("rtc-generic", -1, NULL, 0); |
| if (IS_ERR(pdev)) |
| return PTR_ERR(pdev); |
| |
| return 0; |
| } |
| |
| module_init(rtc_init); |