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Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 1127 |
1 files changed, 1127 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c new file mode 100644 index 000000000..56f44848b --- /dev/null +++ b/arch/powerpc/kernel/time.c @@ -0,0 +1,1127 @@ +/* + * 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/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 <asm/trace.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> + +/* powerpc clocksource/clockevent code */ + +#include <linux/clockchips.h> +#include <linux/timekeeper_internal.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), + .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), + .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); + +struct clock_event_device decrementer_clockevent = { + .name = "decrementer", + .rating = 200, + .irq = 0, + .set_next_event = decrementer_set_next_event, + .set_mode = decrementer_set_mode, + .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 +/* + * Factors for converting from cputime_t (timebase ticks) to + * jiffies, microseconds, 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_usec_factor; +EXPORT_SYMBOL(__cputime_usec_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); + +cputime_t cputime_one_jiffy; + +void (*dtl_consumer)(struct dtl_entry *, u64); + +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(1000000, 0, tb_ticks_per_sec, &res); + __cputime_usec_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 SPURR on systems that have it, otherwise the PURR, + * or if that doesn't exist return the timebase value passed in. + */ +static u64 read_spurr(u64 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 accumulate_stolen_time(void) +{ + u64 sst, ust; + + u8 save_soft_enabled = local_paca->soft_enabled; + + /* 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 + */ + local_paca->soft_enabled = 0; + + sst = scan_dispatch_log(local_paca->starttime_user); + ust = scan_dispatch_log(local_paca->starttime); + local_paca->system_time -= sst; + local_paca->user_time -= ust; + local_paca->stolen_time += ust + sst; + + local_paca->soft_enabled = save_soft_enabled; +} + +static inline u64 calculate_stolen_time(u64 stop_tb) +{ + u64 stolen = 0; + + if (get_paca()->dtl_ridx != be64_to_cpu(get_lppaca()->dtl_idx)) { + stolen = scan_dispatch_log(stop_tb); + get_paca()->system_time -= stolen; + } + + stolen += get_paca()->stolen_time; + get_paca()->stolen_time = 0; + return stolen; +} + +#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 u64 vtime_delta(struct task_struct *tsk, + u64 *sys_scaled, u64 *stolen) +{ + u64 now, nowscaled, deltascaled; + u64 udelta, delta, user_scaled; + + WARN_ON_ONCE(!irqs_disabled()); + + now = mftb(); + nowscaled = read_spurr(now); + get_paca()->system_time += now - get_paca()->starttime; + get_paca()->starttime = now; + deltascaled = nowscaled - get_paca()->startspurr; + get_paca()->startspurr = nowscaled; + + *stolen = calculate_stolen_time(now); + + delta = get_paca()->system_time; + get_paca()->system_time = 0; + udelta = get_paca()->user_time - get_paca()->utime_sspurr; + get_paca()->utime_sspurr = get_paca()->user_time; + + /* + * 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. + */ + *sys_scaled = delta; + user_scaled = udelta; + if (deltascaled != delta + udelta) { + if (udelta) { + *sys_scaled = deltascaled * delta / (delta + udelta); + user_scaled = deltascaled - *sys_scaled; + } else { + *sys_scaled = deltascaled; + } + } + get_paca()->user_time_scaled += user_scaled; + + return delta; +} + +void vtime_account_system(struct task_struct *tsk) +{ + u64 delta, sys_scaled, stolen; + + delta = vtime_delta(tsk, &sys_scaled, &stolen); + account_system_time(tsk, 0, delta, sys_scaled); + if (stolen) + account_steal_time(stolen); +} +EXPORT_SYMBOL_GPL(vtime_account_system); + +void vtime_account_idle(struct task_struct *tsk) +{ + u64 delta, sys_scaled, stolen; + + delta = vtime_delta(tsk, &sys_scaled, &stolen); + account_idle_time(delta + stolen); +} + +/* + * Transfer the user time accumulated in the paca + * by the exception entry and exit code to the generic + * process user time records. + * 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_account_user(struct task_struct *tsk) +{ + cputime_t utime, utimescaled; + + utime = get_paca()->user_time; + utimescaled = get_paca()->user_time_scaled; + get_paca()->user_time = 0; + get_paca()->user_time_scaled = 0; + get_paca()->utime_sspurr = 0; + account_user_time(tsk, utime, utimescaled); +} + +#else /* ! CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ +#define calc_cputime_factors() +#endif + +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); + +#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) +{ + 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 */ + +static void __timer_interrupt(void) +{ + struct pt_regs *regs = get_irq_regs(); + u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); + struct clock_event_device *evt = this_cpu_ptr(&decrementers); + u64 now; + + 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((int)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); + } + +#ifdef CONFIG_PPC64 + /* collect purr register values often, for accurate calculations */ + if (firmware_has_feature(FW_FEATURE_SPLPAR)) { + struct cpu_usage *cu = this_cpu_ptr(&cpu_usage_array); + cu->current_tb = mfspr(SPRN_PURR); + } +#endif + + trace_timer_interrupt_exit(regs); +} + +/* + * timer_interrupt - gets called when the decrementer overflows, + * with interrupts disabled. + */ +void timer_interrupt(struct pt_regs * regs) +{ + struct pt_regs *old_regs; + u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); + + /* Ensure a positive value is written to the decrementer, or else + * some CPUs will continue to take decrementer exceptions. + */ + set_dec(DECREMENTER_MAX); + + /* 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 (!cpu_online(smp_processor_id())) { + *next_tb = ~(u64)0; + return; + } + + /* 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(); + + __timer_interrupt(); + irq_exit(); + set_irq_regs(old_regs); +} + +/* + * 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. + */ +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() - cputime_to_nsecs(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) + /* 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 /* defined(CONFIG_BOOKE) || defined(CONFIG_40x) */ +} + +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_clock(struct timespec now) +{ + struct rtc_time tm; + + if (!ppc_md.set_rtc_time) + return -ENODEV; + + to_tm(now.tv_sec + 1 + timezone_offset, &tm); + tm.tm_year -= 1900; + tm.tm_mon -= 1; + + return ppc_md.set_rtc_time(&tm); +} + +static void __read_persistent_clock(struct timespec *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 = mktime(tm.tm_year+1900, tm.tm_mon+1, tm.tm_mday, + tm.tm_hour, tm.tm_min, tm.tm_sec); +} + +void read_persistent_clock(struct timespec *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 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_old(struct timespec *wall_time, struct timespec *wtm, + struct clocksource *clock, u32 mult, cycle_t cycle_last) +{ + u64 new_tb_to_xs, new_stamp_xsec; + u32 frac_sec; + + if (clock != &clocksource_timebase) + return; + + /* Make userspace gettimeofday spin until we're done. */ + ++vdso_data->tb_update_count; + smp_mb(); + + /* 19342813113834067 ~= 2^(20+64) / 1e9 */ + new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift); + new_stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC; + do_div(new_stamp_xsec, 1000000000); + new_stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC; + + BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC); + /* this is tv_nsec / 1e9 as a 0.32 fraction */ + frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32; + + /* + * 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 = cycle_last; + vdso_data->stamp_xsec = new_stamp_xsec; + vdso_data->tb_to_xs = new_tb_to_xs; + vdso_data->wtom_clock_sec = wtm->tv_sec; + vdso_data->wtom_clock_nsec = wtm->tv_nsec; + vdso_data->stamp_xtime = *wall_time; + vdso_data->stamp_sec_fraction = frac_sec; + 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 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); +} + +/* Interrupt handler for the timer broadcast IPI */ +void tick_broadcast_ipi_handler(void) +{ + u64 *next_tb = this_cpu_ptr(&decrementers_next_tb); + + *next_tb = get_tb_or_rtc(); + __timer_interrupt(); +} + +static void register_decrementer_clockevent(int cpu) +{ + struct clock_event_device *dec = &per_cpu(decrementers, cpu); + + *dec = decrementer_clockevent; + dec->cpumask = cpumask_of(cpu); + + printk_once(KERN_DEBUG "clockevent: %s mult[%x] 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(); + + clockevents_calc_mult_shift(&decrementer_clockevent, ppc_tb_freq, 4); + + 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) +{ + /* 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(); + setup_cputime_one_jiffy(); + + /* + * 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; + + /* 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 +} + + +#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; +} +EXPORT_SYMBOL_GPL(GregorianDay); + +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); +} +EXPORT_SYMBOL(to_tm); + +/* + * 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; +} + +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); + + return PTR_ERR_OR_ZERO(pdev); +} + +module_init(rtc_init); |