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Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 1047 |
1 files changed, 1047 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c new file mode 100644 index 000000000..285159e65 --- /dev/null +++ b/arch/powerpc/kernel/time.c @@ -0,0 +1,1047 @@ +// 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 <linux/errno.h> +#include <linux/export.h> +#include <linux/sched.h> +#include <linux/sched/clock.h> +#include <linux/sched/cputime.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 <linux/delay.h> +#include <linux/irq_work.h> +#include <linux/of_clk.h> +#include <linux/suspend.h> +#include <linux/processor.h> +#include <linux/mc146818rtc.h> +#include <linux/platform_device.h> + +#include <asm/trace.h> +#include <asm/interrupt.h> +#include <asm/io.h> +#include <asm/nvram.h> +#include <asm/cache.h> +#include <asm/machdep.h> +#include <linux/uaccess.h> +#include <asm/time.h> +#include <asm/irq.h> +#include <asm/div64.h> +#include <asm/smp.h> +#include <asm/vdso_datapage.h> +#include <asm/firmware.h> +#include <asm/mce.h> + +/* powerpc clocksource/clockevent code */ + +#include <linux/clockchips.h> +#include <linux/timekeeper_internal.h> + +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_t 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 +/* + * Factor for converting from cputime_t (timebase ticks) to + * microseconds. This is stored as 0.64 fixed-point binary fraction. + */ +u64 __cputime_usec_factor; +EXPORT_SYMBOL(__cputime_usec_factor); + +static void calc_cputime_factors(void) +{ + struct div_result res; + + div128_by_32(1000000, 0, tb_ticks_per_sec, &res); + __cputime_usec_factor = res.result_low; +} + +/* + * 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; +} + +#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ +#define calc_cputime_factors() +#endif + +void __no_kcsan __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 __no_kcsan 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(regs)) { + /* + * 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; + calc_cputime_factors(); + + /* + * 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 |