// SPDX-License-Identifier: GPL-2.0-or-later /* * 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 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 */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* powerpc clocksource/clockevent code */ #include #include static u64 timebase_read(struct clocksource *); static struct clocksource clocksource_timebase = { .name = "timebase", .rating = 400, .flags = CLOCK_SOURCE_IS_CONTINUOUS, .mask = CLOCKSOURCE_MASK(64), .read = timebase_read, .vdso_clock_mode = VDSO_CLOCKMODE_ARCHTIMER, }; #define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF u64 decrementer_max = DECREMENTER_DEFAULT_MAX; EXPORT_SYMBOL_GPL(decrementer_max); /* for KVM HDEC */ static int decrementer_set_next_event(unsigned long evt, struct clock_event_device *dev); static int decrementer_shutdown(struct clock_event_device *evt); struct clock_event_device decrementer_clockevent = { .name = "decrementer", .rating = 200, .irq = 0, .set_next_event = decrementer_set_next_event, .set_state_oneshot_stopped = decrementer_shutdown, .set_state_shutdown = decrementer_shutdown, .tick_resume = decrementer_shutdown, .features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP, }; EXPORT_SYMBOL(decrementer_clockevent); /* * This always puts next_tb beyond now, so the clock event will never fire * with the usual comparison, no need for a separate test for stopped. */ #define DEC_CLOCKEVENT_STOPPED ~0ULL DEFINE_PER_CPU(u64, decrementers_next_tb) = DEC_CLOCKEVENT_STOPPED; EXPORT_SYMBOL_GPL(decrementers_next_tb); static DEFINE_PER_CPU(struct clock_event_device, decrementers); #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 conversions */ 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 u64 boot_tb __read_mostly; extern struct timezone sys_tz; static long timezone_offset; unsigned long ppc_proc_freq; EXPORT_SYMBOL_GPL(ppc_proc_freq); unsigned long ppc_tb_freq; EXPORT_SYMBOL_GPL(ppc_tb_freq); bool tb_invalid; #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE /* * Read the SPURR on systems that have it, otherwise the PURR, * or if that doesn't exist return the timebase value passed in. */ static inline unsigned long read_spurr(unsigned long tb) { if (cpu_has_feature(CPU_FTR_SPURR)) return mfspr(SPRN_SPURR); if (cpu_has_feature(CPU_FTR_PURR)) return mfspr(SPRN_PURR); return tb; } /* * Account time for a transition between system, hard irq * or soft irq state. */ static unsigned long vtime_delta_scaled(struct cpu_accounting_data *acct, unsigned long now, unsigned long stime) { unsigned long stime_scaled = 0; #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME unsigned long nowscaled, deltascaled; unsigned long utime, utime_scaled; nowscaled = read_spurr(now); deltascaled = nowscaled - acct->startspurr; acct->startspurr = nowscaled; utime = acct->utime - acct->utime_sspurr; acct->utime_sspurr = acct->utime; /* * Because we don't read the SPURR on every kernel entry/exit, * deltascaled includes both user and system SPURR ticks. * Apportion these ticks to system SPURR ticks and user * SPURR ticks in the same ratio as the system time (delta) * and user time (udelta) values obtained from the timebase * over the same interval. The system ticks get accounted here; * the user ticks get saved up in paca->user_time_scaled to be * used by account_process_tick. */ stime_scaled = stime; utime_scaled = utime; if (deltascaled != stime + utime) { if (utime) { stime_scaled = deltascaled * stime / (stime + utime); utime_scaled = deltascaled - stime_scaled; } else { stime_scaled = deltascaled; } } acct->utime_scaled += utime_scaled; #endif return stime_scaled; } static unsigned long vtime_delta(struct cpu_accounting_data *acct, unsigned long *stime_scaled, unsigned long *steal_time) { unsigned long now, stime; WARN_ON_ONCE(!irqs_disabled()); now = mftb(); stime = now - acct->starttime; acct->starttime = now; *stime_scaled = vtime_delta_scaled(acct, now, stime); if (IS_ENABLED(CONFIG_PPC_SPLPAR) && firmware_has_feature(FW_FEATURE_SPLPAR)) *steal_time = pseries_calculate_stolen_time(now); else *steal_time = 0; return stime; } static void vtime_delta_kernel(struct cpu_accounting_data *acct, unsigned long *stime, unsigned long *stime_scaled) { unsigned long steal_time; *stime = vtime_delta(acct, stime_scaled, &steal_time); *stime -= min(*stime, steal_time); acct->steal_time += steal_time; } void vtime_account_kernel(struct task_struct *tsk) { struct cpu_accounting_data *acct = get_accounting(tsk); unsigned long stime, stime_scaled; vtime_delta_kernel(acct, &stime, &stime_scaled); if (tsk->flags & PF_VCPU) { acct->gtime += stime; #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME acct->utime_scaled += stime_scaled; #endif } else { acct->stime += stime; #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME acct->stime_scaled += stime_scaled; #endif } } EXPORT_SYMBOL_GPL(vtime_account_kernel); void vtime_account_idle(struct task_struct *tsk) { unsigned long stime, stime_scaled, steal_time; struct cpu_accounting_data *acct = get_accounting(tsk); stime = vtime_delta(acct, &stime_scaled, &steal_time); acct->idle_time += stime + steal_time; } static void vtime_account_irq_field(struct cpu_accounting_data *acct, unsigned long *field) { unsigned long stime, stime_scaled; vtime_delta_kernel(acct, &stime, &stime_scaled); *field += stime; #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME acct->stime_scaled += stime_scaled; #endif } void vtime_account_softirq(struct task_struct *tsk) { struct cpu_accounting_data *acct = get_accounting(tsk); vtime_account_irq_field(acct, &acct->softirq_time); } void vtime_account_hardirq(struct task_struct *tsk) { struct cpu_accounting_data *acct = get_accounting(tsk); vtime_account_irq_field(acct, &acct->hardirq_time); } static void vtime_flush_scaled(struct task_struct *tsk, struct cpu_accounting_data *acct) { #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME if (acct->utime_scaled) tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); if (acct->stime_scaled) tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); acct->utime_scaled = 0; acct->utime_sspurr = 0; acct->stime_scaled = 0; #endif } /* * Account the whole cputime accumulated in the paca * Must be called with interrupts disabled. * Assumes that vtime_account_kernel/idle() has been called * recently (i.e. since the last entry from usermode) so that * get_paca()->user_time_scaled is up to date. */ void vtime_flush(struct task_struct *tsk) { struct cpu_accounting_data *acct = get_accounting(tsk); if (acct->utime) account_user_time(tsk, cputime_to_nsecs(acct->utime)); if (acct->gtime) account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); if (IS_ENABLED(CONFIG_PPC_SPLPAR) && acct->steal_time) { account_steal_time(cputime_to_nsecs(acct->steal_time)); acct->steal_time = 0; } if (acct->idle_time) account_idle_time(cputime_to_nsecs(acct->idle_time)); if (acct->stime) account_system_index_time(tsk, cputime_to_nsecs(acct->stime), CPUTIME_SYSTEM); if (acct->hardirq_time) account_system_index_time(tsk, cputime_to_nsecs(acct->hardirq_time), CPUTIME_IRQ); if (acct->softirq_time) account_system_index_time(tsk, cputime_to_nsecs(acct->softirq_time), CPUTIME_SOFTIRQ); vtime_flush_scaled(tsk, acct); acct->utime = 0; acct->gtime = 0; acct->idle_time = 0; acct->stime = 0; acct->hardirq_time = 0; acct->softirq_time = 0; } #endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ void __delay(unsigned long loops) { unsigned long start; spin_begin(); if (tb_invalid) { /* * TB is in error state and isn't ticking anymore. * HMI handler was unable to recover from TB error. * Return immediately, so that kernel won't get stuck here. */ spin_cpu_relax(); } else { start = mftb(); while (mftb() - start < loops) spin_cpu_relax(); } spin_end(); } EXPORT_SYMBOL(__delay); void udelay(unsigned long usecs) { __delay(tb_ticks_per_usec * usecs); } EXPORT_SYMBOL(udelay); #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_IRQ_WORK /* * 64-bit uses a byte in the PACA, 32-bit uses a per-cpu variable... */ #ifdef CONFIG_PPC64 static inline unsigned long test_irq_work_pending(void) { unsigned long x; asm volatile("lbz %0,%1(13)" : "=r" (x) : "i" (offsetof(struct paca_struct, irq_work_pending))); return x; } static inline void set_irq_work_pending_flag(void) { asm volatile("stb %0,%1(13)" : : "r" (1), "i" (offsetof(struct paca_struct, irq_work_pending))); } static inline void clear_irq_work_pending(void) { asm volatile("stb %0,%1(13)" : : "r" (0), "i" (offsetof(struct paca_struct, irq_work_pending))); } #else /* 32-bit */ DEFINE_PER_CPU(u8, irq_work_pending); #define set_irq_work_pending_flag() __this_cpu_write(irq_work_pending, 1) #define test_irq_work_pending() __this_cpu_read(irq_work_pending) #define clear_irq_work_pending() __this_cpu_write(irq_work_pending, 0) #endif /* 32 vs 64 bit */ void arch_irq_work_raise(void) { /* * 64-bit code that uses irq soft-mask can just cause an immediate * interrupt here that gets soft masked, if this is called under * local_irq_disable(). It might be possible to prevent that happening * by noticing interrupts are disabled and setting decrementer pending * to be replayed when irqs are enabled. The problem there is that * tracing can call irq_work_raise, including in code that does low * level manipulations of irq soft-mask state (e.g., trace_hardirqs_on) * which could get tangled up if we're messing with the same state * here. */ preempt_disable(); set_irq_work_pending_flag(); set_dec(1); preempt_enable(); } static void set_dec_or_work(u64 val) { set_dec(val); /* We may have raced with new irq work */ if (unlikely(test_irq_work_pending())) set_dec(1); } #else /* CONFIG_IRQ_WORK */ #define test_irq_work_pending() 0 #define clear_irq_work_pending() static void set_dec_or_work(u64 val) { set_dec(val); } #endif /* CONFIG_IRQ_WORK */ #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE void timer_rearm_host_dec(u64 now) { u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); WARN_ON_ONCE(!arch_irqs_disabled()); WARN_ON_ONCE(mfmsr() & MSR_EE); if (now >= *next_tb) { local_paca->irq_happened |= PACA_IRQ_DEC; } else { now = *next_tb - now; if (now > decrementer_max) now = decrementer_max; set_dec_or_work(now); } } EXPORT_SYMBOL_GPL(timer_rearm_host_dec); #endif /* * timer_interrupt - gets called when the decrementer overflows, * with interrupts disabled. */ DEFINE_INTERRUPT_HANDLER_ASYNC(timer_interrupt) { struct clock_event_device *evt = this_cpu_ptr(&decrementers); u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); struct pt_regs *old_regs; u64 now; /* * Some implementations of hotplug will get timer interrupts while * offline, just ignore these. */ if (unlikely(!cpu_online(smp_processor_id()))) { set_dec(decrementer_max); return; } /* Conditionally hard-enable interrupts. */ if (should_hard_irq_enable()) { /* * Ensure a positive value is written to the decrementer, or * else some CPUs will continue to take decrementer exceptions. * When the PPC_WATCHDOG (decrementer based) is configured, * keep this at most 31 bits, which is about 4 seconds on most * systems, which gives the watchdog a chance of catching timer * interrupt hard lockups. */ if (IS_ENABLED(CONFIG_PPC_WATCHDOG)) set_dec(0x7fffffff); else set_dec(decrementer_max); do_hard_irq_enable(); } #if defined(CONFIG_PPC32) && defined(CONFIG_PPC_PMAC) if (atomic_read(&ppc_n_lost_interrupts) != 0) __do_IRQ(regs); #endif old_regs = set_irq_regs(regs); trace_timer_interrupt_entry(regs); if (test_irq_work_pending()) { clear_irq_work_pending(); mce_run_irq_context_handlers(); irq_work_run(); } now = get_tb(); if (now >= *next_tb) { evt->event_handler(evt); __this_cpu_inc(irq_stat.timer_irqs_event); } else { now = *next_tb - now; if (now > decrementer_max) now = decrementer_max; set_dec_or_work(now); __this_cpu_inc(irq_stat.timer_irqs_others); } trace_timer_interrupt_exit(regs); set_irq_regs(old_regs); } EXPORT_SYMBOL(timer_interrupt); #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST void timer_broadcast_interrupt(void) { tick_receive_broadcast(); __this_cpu_inc(irq_stat.broadcast_irqs_event); } #endif #ifdef CONFIG_SUSPEND /* 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(); /* Disable the decrementer, so that it doesn't interfere * with suspending. */ set_dec(decrementer_max); local_irq_disable(); set_dec(decrementer_max); } /* Overrides the weak version in kernel/power/main.c */ void arch_suspend_enable_irqs(void) { local_irq_enable(); if (ppc_md.suspend_enable_irqs) ppc_md.suspend_enable_irqs(); } #endif unsigned long long tb_to_ns(unsigned long long ticks) { return mulhdu(ticks, tb_to_ns_scale) << tb_to_ns_shift; } EXPORT_SYMBOL_GPL(tb_to_ns); /* * 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. */ notrace unsigned long long sched_clock(void) { return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; } #ifdef CONFIG_PPC_PSERIES /* * Running clock - attempts to give a view of time passing for a virtualised * kernels. * Uses the VTB register if available otherwise a next best guess. */ unsigned long long running_clock(void) { /* * Don't read the VTB as a host since KVM does not switch in host * timebase into the VTB when it takes a guest off the CPU, reading the * VTB would result in reading 'last switched out' guest VTB. * * Host kernels are often compiled with CONFIG_PPC_PSERIES checked, it * would be unsafe to rely only on the #ifdef above. */ if (firmware_has_feature(FW_FEATURE_LPAR) && cpu_has_feature(CPU_FTR_ARCH_207S)) return mulhdu(get_vtb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; /* * This is a next best approximation without a VTB. * On a host which is running bare metal there should never be any stolen * time and on a host which doesn't do any virtualisation TB *should* equal * VTB so it makes no difference anyway. */ return local_clock() - kcpustat_this_cpu->cpustat[CPUTIME_STEAL]; } #endif static int __init get_freq(char *name, int cells, unsigned long *val) { struct device_node *cpu; const __be32 *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; } static void start_cpu_decrementer(void) { #ifdef CONFIG_BOOKE_OR_40x unsigned int tcr; /* Clear any pending timer interrupts */ mtspr(SPRN_TSR, TSR_ENW | TSR_WIS | TSR_DIS | TSR_FIS); tcr = mfspr(SPRN_TCR); /* * The watchdog may have already been enabled by u-boot. So leave * TRC[WP] (Watchdog Period) alone. */ tcr &= TCR_WP_MASK; /* Clear all bits except for TCR[WP] */ tcr |= TCR_DIE; /* Enable decrementer */ mtspr(SPRN_TCR, tcr); #endif } 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"); } } int update_persistent_clock64(struct timespec64 now) { struct rtc_time tm; if (!ppc_md.set_rtc_time) return -ENODEV; rtc_time64_to_tm(now.tv_sec + 1 + timezone_offset, &tm); return ppc_md.set_rtc_time(&tm); } static void __read_persistent_clock(struct timespec64 *ts) { struct rtc_time tm; static int first = 1; ts->tv_nsec = 0; /* XXX this is a little 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) { ts->tv_sec = ppc_md.get_boot_time() - timezone_offset; return; } } if (!ppc_md.get_rtc_time) { ts->tv_sec = 0; return; } ppc_md.get_rtc_time(&tm); ts->tv_sec = rtc_tm_to_time64(&tm); } void read_persistent_clock64(struct timespec64 *ts) { __read_persistent_clock(ts); /* Sanitize it in case real time clock is set below EPOCH */ if (ts->tv_sec < 0) { ts->tv_sec = 0; ts->tv_nsec = 0; } } /* clocksource code */ static notrace u64 timebase_read(struct clocksource *cs) { return (u64)get_tb(); } static void __init clocksource_init(void) { struct clocksource *clock = &clocksource_timebase; if (clocksource_register_hz(clock, tb_ticks_per_sec)) { 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) { __this_cpu_write(decrementers_next_tb, get_tb() + evt); set_dec_or_work(evt); return 0; } static int decrementer_shutdown(struct clock_event_device *dev) { __this_cpu_write(decrementers_next_tb, DEC_CLOCKEVENT_STOPPED); set_dec_or_work(decrementer_max); return 0; } static void register_decrementer_clockevent(int cpu) { struct clock_event_device *dec = &per_cpu(decrementers, cpu); *dec = decrementer_clockevent; dec->cpumask = cpumask_of(cpu); clockevents_config_and_register(dec, ppc_tb_freq, 2, decrementer_max); printk_once(KERN_DEBUG "clockevent: %s mult[%x] shift[%d] cpu[%d]\n", dec->name, dec->mult, dec->shift, cpu); /* Set values for KVM, see kvm_emulate_dec() */ decrementer_clockevent.mult = dec->mult; decrementer_clockevent.shift = dec->shift; } static void enable_large_decrementer(void) { if (!cpu_has_feature(CPU_FTR_ARCH_300)) return; if (decrementer_max <= DECREMENTER_DEFAULT_MAX) return; /* * If we're running as the hypervisor we need to enable the LD manually * otherwise firmware should have done it for us. */ if (cpu_has_feature(CPU_FTR_HVMODE)) mtspr(SPRN_LPCR, mfspr(SPRN_LPCR) | LPCR_LD); } static void __init set_decrementer_max(void) { struct device_node *cpu; u32 bits = 32; /* Prior to ISAv3 the decrementer is always 32 bit */ if (!cpu_has_feature(CPU_FTR_ARCH_300)) return; cpu = of_find_node_by_type(NULL, "cpu"); if (of_property_read_u32(cpu, "ibm,dec-bits", &bits) == 0) { if (bits > 64 || bits < 32) { pr_warn("time_init: firmware supplied invalid ibm,dec-bits"); bits = 32; } /* calculate the signed maximum given this many bits */ decrementer_max = (1ul << (bits - 1)) - 1; } of_node_put(cpu); pr_info("time_init: %u bit decrementer (max: %llx)\n", bits, decrementer_max); } static void __init init_decrementer_clockevent(void) { register_decrementer_clockevent(smp_processor_id()); } void secondary_cpu_time_init(void) { /* Enable and test the large decrementer for this cpu */ enable_large_decrementer(); /* Start the decrementer on CPUs that have manual control * such as BookE */ start_cpu_decrementer(); /* FIME: Should make unrelated 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) { struct div_result res; u64 scale; unsigned shift; /* 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_ticks_per_jiffy = ppc_tb_freq / HZ; tb_ticks_per_sec = ppc_tb_freq; tb_ticks_per_usec = ppc_tb_freq / 1000000; /* * 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(); /* 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_ticks_per_sec = tb_ticks_per_sec; /* initialise and enable the large decrementer (if we have one) */ set_decrementer_max(); enable_large_decrementer(); /* Start the decrementer on CPUs that have manual control * such as BookE */ start_cpu_decrementer(); /* Register the clocksource */ clocksource_init(); init_decrementer_clockevent(); tick_setup_hrtimer_broadcast(); of_clk_init(NULL); enable_sched_clock_irqtime(); } /* * 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; } /* We don't need to calibrate delay, we use the CPU timebase for that */ void calibrate_delay(void) { /* Some generic code (such as spinlock debug) use loops_per_jiffy * as the number of __delay(1) in a jiffy, so make it so */ loops_per_jiffy = tb_ticks_per_jiffy; } #if IS_ENABLED(CONFIG_RTC_DRV_GENERIC) static int rtc_generic_get_time(struct device *dev, struct rtc_time *tm) { ppc_md.get_rtc_time(tm); return 0; } static int rtc_generic_set_time(struct device *dev, struct rtc_time *tm) { if (!ppc_md.set_rtc_time) return -EOPNOTSUPP; if (ppc_md.set_rtc_time(tm) < 0) return -EOPNOTSUPP; return 0; } static const struct rtc_class_ops rtc_generic_ops = { .read_time = rtc_generic_get_time, .set_time = rtc_generic_set_time, }; static int __init rtc_init(void) { struct platform_device *pdev; if (!ppc_md.get_rtc_time) return -ENODEV; pdev = platform_device_register_data(NULL, "rtc-generic", -1, &rtc_generic_ops, sizeof(rtc_generic_ops)); return PTR_ERR_OR_ZERO(pdev); } device_initcall(rtc_init); #endif