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Diffstat (limited to '')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 1197 |
1 files changed, 1197 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c new file mode 100644 index 000000000..f6c21f6af --- /dev/null +++ b/arch/powerpc/kernel/time.c @@ -0,0 +1,1197 @@ +/* + * 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 + * + * 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/export.h> +#include <linux/sched.h> +#include <linux/sched/clock.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/clockchips.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/clk-provider.h> +#include <linux/suspend.h> +#include <linux/rtc.h> +#include <linux/sched/cputime.h> +#include <linux/processor.h> +#include <asm/trace.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/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/asm-prototypes.h> + +/* powerpc clocksource/clockevent code */ + +#include <linux/clockchips.h> +#include <linux/timekeeper_internal.h> + +static u64 rtc_read(struct clocksource *); +static struct clocksource clocksource_rtc = { + .name = "rtc", + .rating = 400, + .flags = CLOCK_SOURCE_IS_CONTINUOUS, + .mask = CLOCKSOURCE_MASK(64), + .read = rtc_read, +}; + +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, +}; + +#define DECREMENTER_DEFAULT_MAX 0x7FFFFFFF +u64 decrementer_max = DECREMENTER_DEFAULT_MAX; + +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_shutdown = decrementer_shutdown, + .tick_resume = decrementer_shutdown, + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_C3STOP, +}; +EXPORT_SYMBOL(decrementer_clockevent); + +DEFINE_PER_CPU(u64, 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); + +#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); + +#ifdef CONFIG_PPC_SPLPAR +void (*dtl_consumer)(struct dtl_entry *, u64); +#endif + +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 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; +} + +#ifdef CONFIG_PPC_SPLPAR + +/* + * Scan the dispatch trace log and count up the stolen time. + * Should be called with interrupts disabled. + */ +static u64 scan_dispatch_log(u64 stop_tb) +{ + u64 i = local_paca->dtl_ridx; + struct dtl_entry *dtl = local_paca->dtl_curr; + struct dtl_entry *dtl_end = local_paca->dispatch_log_end; + struct lppaca *vpa = local_paca->lppaca_ptr; + u64 tb_delta; + u64 stolen = 0; + u64 dtb; + + if (!dtl) + return 0; + + if (i == be64_to_cpu(vpa->dtl_idx)) + return 0; + while (i < be64_to_cpu(vpa->dtl_idx)) { + dtb = be64_to_cpu(dtl->timebase); + tb_delta = be32_to_cpu(dtl->enqueue_to_dispatch_time) + + be32_to_cpu(dtl->ready_to_enqueue_time); + barrier(); + if (i + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx)) { + /* buffer has overflowed */ + i = be64_to_cpu(vpa->dtl_idx) - N_DISPATCH_LOG; + dtl = local_paca->dispatch_log + (i % N_DISPATCH_LOG); + continue; + } + if (dtb > stop_tb) + break; + if (dtl_consumer) + dtl_consumer(dtl, i); + stolen += tb_delta; + ++i; + ++dtl; + if (dtl == dtl_end) + dtl = local_paca->dispatch_log; + } + local_paca->dtl_ridx = i; + local_paca->dtl_curr = dtl; + return stolen; +} + +/* + * Accumulate stolen time by scanning the dispatch trace log. + * Called on entry from user mode. + */ +void notrace accumulate_stolen_time(void) +{ + u64 sst, ust; + unsigned long save_irq_soft_mask = irq_soft_mask_return(); + struct cpu_accounting_data *acct = &local_paca->accounting; + + /* We are called early in the exception entry, before + * soft/hard_enabled are sync'ed to the expected state + * for the exception. We are hard disabled but the PACA + * needs to reflect that so various debug stuff doesn't + * complain + */ + irq_soft_mask_set(IRQS_DISABLED); + + sst = scan_dispatch_log(acct->starttime_user); + ust = scan_dispatch_log(acct->starttime); + acct->stime -= sst; + acct->utime -= ust; + acct->steal_time += ust + sst; + + irq_soft_mask_set(save_irq_soft_mask); +} + +static inline u64 calculate_stolen_time(u64 stop_tb) +{ + if (!firmware_has_feature(FW_FEATURE_SPLPAR)) + return 0; + + if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) + return scan_dispatch_log(stop_tb); + + return 0; +} + +#else /* CONFIG_PPC_SPLPAR */ +static inline u64 calculate_stolen_time(u64 stop_tb) +{ + return 0; +} + +#endif /* CONFIG_PPC_SPLPAR */ + +/* + * Account time for a transition between system, hard irq + * or soft irq state. + */ +static unsigned long vtime_delta(struct task_struct *tsk, + unsigned long *stime_scaled, + unsigned long *steal_time) +{ + unsigned long now, nowscaled, deltascaled; + unsigned long stime; + unsigned long utime, utime_scaled; + struct cpu_accounting_data *acct = get_accounting(tsk); + + WARN_ON_ONCE(!irqs_disabled()); + + now = mftb(); + nowscaled = read_spurr(now); + stime = now - acct->starttime; + acct->starttime = now; + deltascaled = nowscaled - acct->startspurr; + acct->startspurr = nowscaled; + + *steal_time = calculate_stolen_time(now); + + 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; + + return stime; +} + +void vtime_account_system(struct task_struct *tsk) +{ + unsigned long stime, stime_scaled, steal_time; + struct cpu_accounting_data *acct = get_accounting(tsk); + + stime = vtime_delta(tsk, &stime_scaled, &steal_time); + + stime -= min(stime, steal_time); + acct->steal_time += steal_time; + + if ((tsk->flags & PF_VCPU) && !irq_count()) { + acct->gtime += stime; + acct->utime_scaled += stime_scaled; + } else { + if (hardirq_count()) + acct->hardirq_time += stime; + else if (in_serving_softirq()) + acct->softirq_time += stime; + else + acct->stime += stime; + + acct->stime_scaled += stime_scaled; + } +} +EXPORT_SYMBOL_GPL(vtime_account_system); + +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(tsk, &stime_scaled, &steal_time); + acct->idle_time += stime + steal_time; +} + +/* + * Account the whole cputime accumulated in the paca + * Must be called with interrupts disabled. + * Assumes that vtime_account_system/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->utime_scaled) + tsk->utimescaled += cputime_to_nsecs(acct->utime_scaled); + + if (acct->gtime) + account_guest_time(tsk, cputime_to_nsecs(acct->gtime)); + + if (acct->steal_time) + account_steal_time(cputime_to_nsecs(acct->steal_time)); + + 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->stime_scaled) + tsk->stimescaled += cputime_to_nsecs(acct->stime_scaled); + + 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); + + acct->utime = 0; + acct->utime_scaled = 0; + acct->utime_sspurr = 0; + acct->gtime = 0; + acct->steal_time = 0; + acct->idle_time = 0; + acct->stime = 0; + acct->stime_scaled = 0; + acct->hardirq_time = 0; + acct->softirq_time = 0; +} + +#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ +#define calc_cputime_factors() +#endif + +void __delay(unsigned long loops) +{ + unsigned long start; + int diff; + + spin_begin(); + if (__USE_RTC()) { + start = get_rtcl(); + do { + /* the RTCL register wraps at 1000000000 */ + diff = get_rtcl() - start; + if (diff < 0) + diff += 1000000000; + spin_cpu_relax(); + } while (diff < loops); + } else { + start = get_tbl(); + while (get_tbl() - 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(); +} + +#else /* CONFIG_IRQ_WORK */ + +#define test_irq_work_pending() 0 +#define clear_irq_work_pending() + +#endif /* CONFIG_IRQ_WORK */ + +/* + * timer_interrupt - gets called when the decrementer overflows, + * with interrupts disabled. + */ +void timer_interrupt(struct pt_regs *regs) +{ + 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 and we also need to set + * decrementers_next_tb as MAX to make sure __check_irq_replay + * don't replay timer interrupt when return, otherwise we'll trap + * here infinitely :( + */ + if (unlikely(!cpu_online(smp_processor_id()))) { + *next_tb = ~(u64)0; + set_dec(decrementer_max); + return; + } + + /* 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); + + /* Conditionally hard-enable interrupts now that the DEC has been + * bumped to its maximum value + */ + may_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); + irq_enter(); + trace_timer_interrupt_entry(regs); + + if (test_irq_work_pending()) { + clear_irq_work_pending(); + irq_work_run(); + } + + now = get_tb_or_rtc(); + if (now >= *next_tb) { + *next_tb = ~(u64)0; + if (evt->event_handler) + evt->event_handler(evt); + __this_cpu_inc(irq_stat.timer_irqs_event); + } else { + now = *next_tb - now; + if (now <= decrementer_max) + set_dec(now); + /* We may have raced with new irq work */ + if (test_irq_work_pending()) + set_dec(1); + __this_cpu_inc(irq_stat.timer_irqs_others); + } + + trace_timer_interrupt_exit(regs); + irq_exit(); + set_irq_regs(old_regs); +} +EXPORT_SYMBOL(timer_interrupt); + +#ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST +void timer_broadcast_interrupt(void) +{ + u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); + + *next_tb = ~(u64)0; + tick_receive_broadcast(); + __this_cpu_inc(irq_stat.broadcast_irqs_event); +} +#endif + +/* + * Hypervisor decrementer interrupts shouldn't occur but are sometimes + * left pending on exit from a KVM guest. We don't need to do anything + * to clear them, as they are edge-triggered. + */ +void hdec_interrupt(struct pt_regs *regs) +{ +} + +#ifdef CONFIG_SUSPEND +static void generic_suspend_disable_irqs(void) +{ + /* Disable the decrementer, so that it doesn't interfere + * with suspending. + */ + + set_dec(decrementer_max); + local_irq_disable(); + set_dec(decrementer_max); +} + +static void generic_suspend_enable_irqs(void) +{ + local_irq_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 + +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) +{ + if (__USE_RTC()) + return get_rtc(); + 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) +{ +#if defined(CONFIG_BOOKE) || defined(CONFIG_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 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) { + 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 rtc_read(struct clocksource *cs) +{ + return (u64)get_rtc(); +} + +static notrace u64 timebase_read(struct clocksource *cs) +{ + return (u64)get_tb(); +} + + +void update_vsyscall(struct timekeeper *tk) +{ + struct timespec xt; + struct clocksource *clock = tk->tkr_mono.clock; + u32 mult = tk->tkr_mono.mult; + u32 shift = tk->tkr_mono.shift; + u64 cycle_last = tk->tkr_mono.cycle_last; + u64 new_tb_to_xs, new_stamp_xsec; + u64 frac_sec; + + if (clock != &clocksource_timebase) + return; + + xt.tv_sec = tk->xtime_sec; + xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift); + + /* Make userspace gettimeofday spin until we're done. */ + ++vdso_data->tb_update_count; + smp_mb(); + + /* + * This computes ((2^20 / 1e9) * mult) >> shift as a + * 0.64 fixed-point fraction. + * The computation in the else clause below won't overflow + * (as long as the timebase frequency is >= 1.049 MHz) + * but loses precision because we lose the low bits of the constant + * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9. + * For a shift of 24 the error is about 0.5e-9, or about 0.5ns + * over a second. (Shift values are usually 22, 23 or 24.) + * For high frequency clocks such as the 512MHz timebase clock + * on POWER[6789], the mult value is small (e.g. 32768000) + * and so we can shift the constant by 16 initially + * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the + * remaining shifts after the multiplication, which gives a + * more accurate result (e.g. with mult = 32768000, shift = 24, + * the error is only about 1.2e-12, or 0.7ns over 10 minutes). + */ + if (mult <= 62500000 && clock->shift >= 16) + new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16); + else + new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); + + /* + * Compute the fractional second in units of 2^-32 seconds. + * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift + * in nanoseconds, so multiplying that by 2^32 / 1e9 gives + * it in units of 2^-32 seconds. + * We assume shift <= 32 because clocks_calc_mult_shift() + * generates shift values in the range 0 - 32. + */ + frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift); + do_div(frac_sec, NSEC_PER_SEC); + + /* + * Work out new stamp_xsec value for any legacy users of systemcfg. + * stamp_xsec is in units of 2^-20 seconds. + */ + new_stamp_xsec = frac_sec >> 12; + new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC; + + /* + * 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. + */ + vdso_data->tb_orig_stamp = cycle_last; + vdso_data->stamp_xsec = new_stamp_xsec; + vdso_data->tb_to_xs = new_tb_to_xs; + vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec; + vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec; + vdso_data->stamp_xtime = xt; + vdso_data->stamp_sec_fraction = frac_sec; + vdso_data->hrtimer_res = hrtimer_resolution; + smp_wmb(); + ++(vdso_data->tb_update_count); +} + +void update_vsyscall_tz(void) +{ + vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; + vdso_data->tz_dsttime = sys_tz.tz_dsttime; +} + +static void __init clocksource_init(void) +{ + struct clocksource *clock; + + if (__USE_RTC()) + clock = &clocksource_rtc; + else + 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_or_rtc() + evt); + set_dec(evt); + + /* We may have raced with new irq work */ + if (test_irq_work_pending()) + set_dec(1); + + return 0; +} + +static int decrementer_shutdown(struct clock_event_device *dev) +{ + decrementer_set_next_event(decrementer_max, dev); + 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 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) +{ + struct div_result res; + u64 scale; + unsigned shift; + + if (__USE_RTC()) { + /* 601 processor: dec counts down by 128 every 128ns */ + ppc_tb_freq = 1000000000; + } 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_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_or_rtc(); + + /* 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_update_count = 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(); + +#ifdef CONFIG_COMMON_CLK + of_clk_init(NULL); +#endif +} + +/* + * 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 |