From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- arch/i386/kernel/time.c | 476 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 476 insertions(+) create mode 100644 arch/i386/kernel/time.c (limited to 'arch/i386/kernel/time.c') diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c new file mode 100644 index 0000000..9b55e30 --- /dev/null +++ b/arch/i386/kernel/time.c @@ -0,0 +1,476 @@ +/* + * linux/arch/i386/kernel/time.c + * + * Copyright (C) 1991, 1992, 1995 Linus Torvalds + * + * This file contains the PC-specific time handling details: + * reading the RTC at bootup, etc.. + * 1994-07-02 Alan Modra + * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime + * 1995-03-26 Markus Kuhn + * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887 + * precision CMOS clock update + * 1996-05-03 Ingo Molnar + * fixed time warps in do_[slow|fast]_gettimeoffset() + * 1997-09-10 Updated NTP code according to technical memorandum Jan '96 + * "A Kernel Model for Precision Timekeeping" by Dave Mills + * 1998-09-05 (Various) + * More robust do_fast_gettimeoffset() algorithm implemented + * (works with APM, Cyrix 6x86MX and Centaur C6), + * monotonic gettimeofday() with fast_get_timeoffset(), + * drift-proof precision TSC calibration on boot + * (C. Scott Ananian , Andrew D. + * Balsa , Philip Gladstone ; + * ported from 2.0.35 Jumbo-9 by Michael Krause ). + * 1998-12-16 Andrea Arcangeli + * Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy + * because was not accounting lost_ticks. + * 1998-12-24 Copyright (C) 1998 Andrea Arcangeli + * Fixed a xtime SMP race (we need the xtime_lock rw spinlock to + * serialize accesses to xtime/lost_ticks). + */ + +#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 "mach_time.h" + +#include +#include + +#include + +#include + +#include "io_ports.h" + +extern spinlock_t i8259A_lock; +int pit_latch_buggy; /* extern */ + +#include "do_timer.h" + +u64 jiffies_64 = INITIAL_JIFFIES; + +EXPORT_SYMBOL(jiffies_64); + +unsigned long cpu_khz; /* Detected as we calibrate the TSC */ + +extern unsigned long wall_jiffies; + +DEFINE_SPINLOCK(rtc_lock); + +DEFINE_SPINLOCK(i8253_lock); +EXPORT_SYMBOL(i8253_lock); + +struct timer_opts *cur_timer = &timer_none; + +/* + * This is a special lock that is owned by the CPU and holds the index + * register we are working with. It is required for NMI access to the + * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details. + */ +volatile unsigned long cmos_lock = 0; +EXPORT_SYMBOL(cmos_lock); + +/* Routines for accessing the CMOS RAM/RTC. */ +unsigned char rtc_cmos_read(unsigned char addr) +{ + unsigned char val; + lock_cmos_prefix(addr); + outb_p(addr, RTC_PORT(0)); + val = inb_p(RTC_PORT(1)); + lock_cmos_suffix(addr); + return val; +} +EXPORT_SYMBOL(rtc_cmos_read); + +void rtc_cmos_write(unsigned char val, unsigned char addr) +{ + lock_cmos_prefix(addr); + outb_p(addr, RTC_PORT(0)); + outb_p(val, RTC_PORT(1)); + lock_cmos_suffix(addr); +} +EXPORT_SYMBOL(rtc_cmos_write); + +/* + * This version of gettimeofday has microsecond resolution + * and better than microsecond precision on fast x86 machines with TSC. + */ +void do_gettimeofday(struct timeval *tv) +{ + unsigned long seq; + unsigned long usec, sec; + unsigned long max_ntp_tick; + + do { + unsigned long lost; + + seq = read_seqbegin(&xtime_lock); + + usec = cur_timer->get_offset(); + lost = jiffies - wall_jiffies; + + /* + * If time_adjust is negative then NTP is slowing the clock + * so make sure not to go into next possible interval. + * Better to lose some accuracy than have time go backwards.. + */ + if (unlikely(time_adjust < 0)) { + max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj; + usec = min(usec, max_ntp_tick); + + if (lost) + usec += lost * max_ntp_tick; + } + else if (unlikely(lost)) + usec += lost * (USEC_PER_SEC / HZ); + + sec = xtime.tv_sec; + usec += (xtime.tv_nsec / 1000); + } while (read_seqretry(&xtime_lock, seq)); + + while (usec >= 1000000) { + usec -= 1000000; + sec++; + } + + tv->tv_sec = sec; + tv->tv_usec = usec; +} + +EXPORT_SYMBOL(do_gettimeofday); + +int do_settimeofday(struct timespec *tv) +{ + time_t wtm_sec, sec = tv->tv_sec; + long wtm_nsec, nsec = tv->tv_nsec; + + if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + /* + * This is revolting. We need to set "xtime" correctly. However, the + * value in this location is the value at the most recent update of + * wall time. Discover what correction gettimeofday() would have + * made, and then undo it! + */ + nsec -= cur_timer->get_offset() * NSEC_PER_USEC; + nsec -= (jiffies - wall_jiffies) * TICK_NSEC; + + wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); + wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); + + set_normalized_timespec(&xtime, sec, nsec); + set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); + + time_adjust = 0; /* stop active adjtime() */ + time_status |= STA_UNSYNC; + time_maxerror = NTP_PHASE_LIMIT; + time_esterror = NTP_PHASE_LIMIT; + write_sequnlock_irq(&xtime_lock); + clock_was_set(); + return 0; +} + +EXPORT_SYMBOL(do_settimeofday); + +static int set_rtc_mmss(unsigned long nowtime) +{ + int retval; + + WARN_ON(irqs_disabled()); + + /* gets recalled with irq locally disabled */ + spin_lock_irq(&rtc_lock); + if (efi_enabled) + retval = efi_set_rtc_mmss(nowtime); + else + retval = mach_set_rtc_mmss(nowtime); + spin_unlock_irq(&rtc_lock); + + return retval; +} + + +int timer_ack; + +/* monotonic_clock(): returns # of nanoseconds passed since time_init() + * Note: This function is required to return accurate + * time even in the absence of multiple timer ticks. + */ +unsigned long long monotonic_clock(void) +{ + return cur_timer->monotonic_clock(); +} +EXPORT_SYMBOL(monotonic_clock); + +#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER) +unsigned long profile_pc(struct pt_regs *regs) +{ + unsigned long pc = instruction_pointer(regs); + + if (in_lock_functions(pc)) + return *(unsigned long *)(regs->ebp + 4); + + return pc; +} +EXPORT_SYMBOL(profile_pc); +#endif + +/* + * timer_interrupt() needs to keep up the real-time clock, + * as well as call the "do_timer()" routine every clocktick + */ +static inline void do_timer_interrupt(int irq, void *dev_id, + struct pt_regs *regs) +{ +#ifdef CONFIG_X86_IO_APIC + if (timer_ack) { + /* + * Subtle, when I/O APICs are used we have to ack timer IRQ + * manually to reset the IRR bit for do_slow_gettimeoffset(). + * This will also deassert NMI lines for the watchdog if run + * on an 82489DX-based system. + */ + spin_lock(&i8259A_lock); + outb(0x0c, PIC_MASTER_OCW3); + /* Ack the IRQ; AEOI will end it automatically. */ + inb(PIC_MASTER_POLL); + spin_unlock(&i8259A_lock); + } +#endif + + do_timer_interrupt_hook(regs); + + + if (MCA_bus) { + /* The PS/2 uses level-triggered interrupts. You can't + turn them off, nor would you want to (any attempt to + enable edge-triggered interrupts usually gets intercepted by a + special hardware circuit). Hence we have to acknowledge + the timer interrupt. Through some incredibly stupid + design idea, the reset for IRQ 0 is done by setting the + high bit of the PPI port B (0x61). Note that some PS/2s, + notably the 55SX, work fine if this is removed. */ + + irq = inb_p( 0x61 ); /* read the current state */ + outb_p( irq|0x80, 0x61 ); /* reset the IRQ */ + } +} + +/* + * This is the same as the above, except we _also_ save the current + * Time Stamp Counter value at the time of the timer interrupt, so that + * we later on can estimate the time of day more exactly. + */ +irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) +{ + /* + * Here we are in the timer irq handler. We just have irqs locally + * disabled but we don't know if the timer_bh is running on the other + * CPU. We need to avoid to SMP race with it. NOTE: we don' t need + * the irq version of write_lock because as just said we have irq + * locally disabled. -arca + */ + write_seqlock(&xtime_lock); + + cur_timer->mark_offset(); + + do_timer_interrupt(irq, NULL, regs); + + write_sequnlock(&xtime_lock); + return IRQ_HANDLED; +} + +/* not static: needed by APM */ +unsigned long get_cmos_time(void) +{ + unsigned long retval; + + spin_lock(&rtc_lock); + + if (efi_enabled) + retval = efi_get_time(); + else + retval = mach_get_cmos_time(); + + spin_unlock(&rtc_lock); + + return retval; +} +static void sync_cmos_clock(unsigned long dummy); + +static struct timer_list sync_cmos_timer = + TIMER_INITIALIZER(sync_cmos_clock, 0, 0); + +static void sync_cmos_clock(unsigned long dummy) +{ + struct timeval now, next; + int fail = 1; + + /* + * If we have an externally synchronized Linux clock, then update + * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be + * called as close as possible to 500 ms before the new second starts. + * This code is run on a timer. If the clock is set, that timer + * may not expire at the correct time. Thus, we adjust... + */ + if ((time_status & STA_UNSYNC) != 0) + /* + * Not synced, exit, do not restart a timer (if one is + * running, let it run out). + */ + return; + + do_gettimeofday(&now); + if (now.tv_usec >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 && + now.tv_usec <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2) + fail = set_rtc_mmss(now.tv_sec); + + next.tv_usec = USEC_AFTER - now.tv_usec; + if (next.tv_usec <= 0) + next.tv_usec += USEC_PER_SEC; + + if (!fail) + next.tv_sec = 659; + else + next.tv_sec = 0; + + if (next.tv_usec >= USEC_PER_SEC) { + next.tv_sec++; + next.tv_usec -= USEC_PER_SEC; + } + mod_timer(&sync_cmos_timer, jiffies + timeval_to_jiffies(&next)); +} + +void notify_arch_cmos_timer(void) +{ + mod_timer(&sync_cmos_timer, jiffies + 1); +} + +static long clock_cmos_diff, sleep_start; + +static int timer_suspend(struct sys_device *dev, u32 state) +{ + /* + * Estimate time zone so that set_time can update the clock + */ + clock_cmos_diff = -get_cmos_time(); + clock_cmos_diff += get_seconds(); + sleep_start = get_cmos_time(); + return 0; +} + +static int timer_resume(struct sys_device *dev) +{ + unsigned long flags; + unsigned long sec; + unsigned long sleep_length; + +#ifdef CONFIG_HPET_TIMER + if (is_hpet_enabled()) + hpet_reenable(); +#endif + sec = get_cmos_time() + clock_cmos_diff; + sleep_length = (get_cmos_time() - sleep_start) * HZ; + write_seqlock_irqsave(&xtime_lock, flags); + xtime.tv_sec = sec; + xtime.tv_nsec = 0; + write_sequnlock_irqrestore(&xtime_lock, flags); + jiffies += sleep_length; + wall_jiffies += sleep_length; + return 0; +} + +static struct sysdev_class timer_sysclass = { + .resume = timer_resume, + .suspend = timer_suspend, + set_kset_name("timer"), +}; + + +/* XXX this driverfs stuff should probably go elsewhere later -john */ +static struct sys_device device_timer = { + .id = 0, + .cls = &timer_sysclass, +}; + +static int time_init_device(void) +{ + int error = sysdev_class_register(&timer_sysclass); + if (!error) + error = sysdev_register(&device_timer); + return error; +} + +device_initcall(time_init_device); + +#ifdef CONFIG_HPET_TIMER +extern void (*late_time_init)(void); +/* Duplicate of time_init() below, with hpet_enable part added */ +static void __init hpet_time_init(void) +{ + xtime.tv_sec = get_cmos_time(); + xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ); + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + + if (hpet_enable() >= 0) { + printk("Using HPET for base-timer\n"); + } + + cur_timer = select_timer(); + printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name); + + time_init_hook(); +} +#endif + +void __init time_init(void) +{ +#ifdef CONFIG_HPET_TIMER + if (is_hpet_capable()) { + /* + * HPET initialization needs to do memory-mapped io. So, let + * us do a late initialization after mem_init(). + */ + late_time_init = hpet_time_init; + return; + } +#endif + xtime.tv_sec = get_cmos_time(); + xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ); + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + + cur_timer = select_timer(); + printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name); + + time_init_hook(); +} -- cgit v1.1