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Diffstat (limited to 'arch/x86_64/kernel/time.c')
| -rw-r--r-- | arch/x86_64/kernel/time.c | 1262 |
1 files changed, 1262 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c new file mode 100644 index 000000000000..3bafe438fa75 --- /dev/null +++ b/arch/x86_64/kernel/time.c @@ -0,0 +1,1262 @@ +/* + * linux/arch/x86-64/kernel/time.c + * + * "High Precision Event Timer" based timekeeping. + * + * Copyright (c) 1991,1992,1995 Linus Torvalds + * Copyright (c) 1994 Alan Modra + * Copyright (c) 1995 Markus Kuhn + * Copyright (c) 1996 Ingo Molnar + * Copyright (c) 1998 Andrea Arcangeli + * Copyright (c) 2002 Vojtech Pavlik + * Copyright (c) 2003 Andi Kleen + * RTC support code taken from arch/i386/kernel/timers/time_hpet.c + */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/mc146818rtc.h> +#include <linux/irq.h> +#include <linux/time.h> +#include <linux/ioport.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/sysdev.h> +#include <linux/bcd.h> +#include <linux/kallsyms.h> +#include <asm/8253pit.h> +#include <asm/pgtable.h> +#include <asm/vsyscall.h> +#include <asm/timex.h> +#include <asm/proto.h> +#include <asm/hpet.h> +#include <asm/sections.h> +#include <linux/cpufreq.h> +#include <linux/hpet.h> +#ifdef CONFIG_X86_LOCAL_APIC +#include <asm/apic.h> +#endif + +u64 jiffies_64 = INITIAL_JIFFIES; + +EXPORT_SYMBOL(jiffies_64); + +#ifdef CONFIG_CPU_FREQ +static void cpufreq_delayed_get(void); +#endif +extern void i8254_timer_resume(void); +extern int using_apic_timer; + +DEFINE_SPINLOCK(rtc_lock); +DEFINE_SPINLOCK(i8253_lock); + +static int nohpet __initdata = 0; +static int notsc __initdata = 0; + +#undef HPET_HACK_ENABLE_DANGEROUS + +unsigned int cpu_khz; /* TSC clocks / usec, not used here */ +static unsigned long hpet_period; /* fsecs / HPET clock */ +unsigned long hpet_tick; /* HPET clocks / interrupt */ +unsigned long vxtime_hz = PIT_TICK_RATE; +int report_lost_ticks; /* command line option */ +unsigned long long monotonic_base; + +struct vxtime_data __vxtime __section_vxtime; /* for vsyscalls */ + +volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES; +unsigned long __wall_jiffies __section_wall_jiffies = INITIAL_JIFFIES; +struct timespec __xtime __section_xtime; +struct timezone __sys_tz __section_sys_tz; + +static inline void rdtscll_sync(unsigned long *tsc) +{ +#ifdef CONFIG_SMP + sync_core(); +#endif + rdtscll(*tsc); +} + +/* + * do_gettimeoffset() returns microseconds since last timer interrupt was + * triggered by hardware. A memory read of HPET is slower than a register read + * of TSC, but much more reliable. It's also synchronized to the timer + * interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a + * timer interrupt has happened already, but vxtime.trigger wasn't updated yet. + * This is not a problem, because jiffies hasn't updated either. They are bound + * together by xtime_lock. + */ + +static inline unsigned int do_gettimeoffset_tsc(void) +{ + unsigned long t; + unsigned long x; + rdtscll_sync(&t); + if (t < vxtime.last_tsc) t = vxtime.last_tsc; /* hack */ + x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> 32; + return x; +} + +static inline unsigned int do_gettimeoffset_hpet(void) +{ + return ((hpet_readl(HPET_COUNTER) - vxtime.last) * vxtime.quot) >> 32; +} + +unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc; + +/* + * This version of gettimeofday() has microsecond resolution and better than + * microsecond precision, as we're using at least a 10 MHz (usually 14.31818 + * MHz) HPET timer. + */ + +void do_gettimeofday(struct timeval *tv) +{ + unsigned long seq, t; + unsigned int sec, usec; + + do { + seq = read_seqbegin(&xtime_lock); + + sec = xtime.tv_sec; + usec = xtime.tv_nsec / 1000; + + /* i386 does some correction here to keep the clock + monotonous even when ntpd is fixing drift. + But they didn't work for me, there is a non monotonic + clock anyways with ntp. + I dropped all corrections now until a real solution can + be found. Note when you fix it here you need to do the same + in arch/x86_64/kernel/vsyscall.c and export all needed + variables in vmlinux.lds. -AK */ + + t = (jiffies - wall_jiffies) * (1000000L / HZ) + + do_gettimeoffset(); + usec += t; + + } while (read_seqretry(&xtime_lock, seq)); + + tv->tv_sec = sec + usec / 1000000; + tv->tv_usec = usec % 1000000; +} + +EXPORT_SYMBOL(do_gettimeofday); + +/* + * settimeofday() first undoes the correction that gettimeofday would do + * on the time, and then saves it. This is ugly, but has been like this for + * ages already. + */ + +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); + + nsec -= do_gettimeoffset() * 1000 + + (jiffies - wall_jiffies) * (NSEC_PER_SEC/HZ); + + 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); + +unsigned long profile_pc(struct pt_regs *regs) +{ + unsigned long pc = instruction_pointer(regs); + + /* Assume the lock function has either no stack frame or only a single word. + This checks if the address on the stack looks like a kernel text address. + There is a small window for false hits, but in that case the tick + is just accounted to the spinlock function. + Better would be to write these functions in assembler again + and check exactly. */ + if (in_lock_functions(pc)) { + char *v = *(char **)regs->rsp; + if ((v >= _stext && v <= _etext) || + (v >= _sinittext && v <= _einittext) || + (v >= (char *)MODULES_VADDR && v <= (char *)MODULES_END)) + return (unsigned long)v; + return ((unsigned long *)regs->rsp)[1]; + } + return pc; +} +EXPORT_SYMBOL(profile_pc); + +/* + * In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500 + * ms after the second nowtime has started, because when nowtime is written + * into the registers of the CMOS clock, it will jump to the next second + * precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data + * sheet for details. + */ + +static void set_rtc_mmss(unsigned long nowtime) +{ + int real_seconds, real_minutes, cmos_minutes; + unsigned char control, freq_select; + +/* + * IRQs are disabled when we're called from the timer interrupt, + * no need for spin_lock_irqsave() + */ + + spin_lock(&rtc_lock); + +/* + * Tell the clock it's being set and stop it. + */ + + control = CMOS_READ(RTC_CONTROL); + CMOS_WRITE(control | RTC_SET, RTC_CONTROL); + + freq_select = CMOS_READ(RTC_FREQ_SELECT); + CMOS_WRITE(freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT); + + cmos_minutes = CMOS_READ(RTC_MINUTES); + BCD_TO_BIN(cmos_minutes); + +/* + * since we're only adjusting minutes and seconds, don't interfere with hour + * overflow. This avoids messing with unknown time zones but requires your RTC + * not to be off by more than 15 minutes. Since we're calling it only when + * our clock is externally synchronized using NTP, this shouldn't be a problem. + */ + + real_seconds = nowtime % 60; + real_minutes = nowtime / 60; + if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1) + real_minutes += 30; /* correct for half hour time zone */ + real_minutes %= 60; + +#if 0 + /* AMD 8111 is a really bad time keeper and hits this regularly. + It probably was an attempt to avoid screwing up DST, but ignore + that for now. */ + if (abs(real_minutes - cmos_minutes) >= 30) { + printk(KERN_WARNING "time.c: can't update CMOS clock " + "from %d to %d\n", cmos_minutes, real_minutes); + } else +#endif + + { + BIN_TO_BCD(real_seconds); + BIN_TO_BCD(real_minutes); + CMOS_WRITE(real_seconds, RTC_SECONDS); + CMOS_WRITE(real_minutes, RTC_MINUTES); + } + +/* + * The following flags have to be released exactly in this order, otherwise the + * DS12887 (popular MC146818A clone with integrated battery and quartz) will + * not reset the oscillator and will not update precisely 500 ms later. You + * won't find this mentioned in the Dallas Semiconductor data sheets, but who + * believes data sheets anyway ... -- Markus Kuhn + */ + + CMOS_WRITE(control, RTC_CONTROL); + CMOS_WRITE(freq_select, RTC_FREQ_SELECT); + + spin_unlock(&rtc_lock); +} + + +/* 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) +{ + unsigned long seq; + u32 last_offset, this_offset, offset; + unsigned long long base; + + if (vxtime.mode == VXTIME_HPET) { + do { + seq = read_seqbegin(&xtime_lock); + + last_offset = vxtime.last; + base = monotonic_base; + this_offset = hpet_readl(HPET_T0_CMP) - hpet_tick; + + } while (read_seqretry(&xtime_lock, seq)); + offset = (this_offset - last_offset); + offset *=(NSEC_PER_SEC/HZ)/hpet_tick; + return base + offset; + }else{ + do { + seq = read_seqbegin(&xtime_lock); + + last_offset = vxtime.last_tsc; + base = monotonic_base; + } while (read_seqretry(&xtime_lock, seq)); + sync_core(); + rdtscll(this_offset); + offset = (this_offset - last_offset)*1000/cpu_khz; + return base + offset; + } + + +} +EXPORT_SYMBOL(monotonic_clock); + +static noinline void handle_lost_ticks(int lost, struct pt_regs *regs) +{ + static long lost_count; + static int warned; + + if (report_lost_ticks) { + printk(KERN_WARNING "time.c: Lost %d timer " + "tick(s)! ", lost); + print_symbol("rip %s)\n", regs->rip); + } + + if (lost_count == 1000 && !warned) { + printk(KERN_WARNING + "warning: many lost ticks.\n" + KERN_WARNING "Your time source seems to be instable or " + "some driver is hogging interupts\n"); + print_symbol("rip %s\n", regs->rip); + if (vxtime.mode == VXTIME_TSC && vxtime.hpet_address) { + printk(KERN_WARNING "Falling back to HPET\n"); + vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick; + vxtime.mode = VXTIME_HPET; + do_gettimeoffset = do_gettimeoffset_hpet; + } + /* else should fall back to PIT, but code missing. */ + warned = 1; + } else + lost_count++; + +#ifdef CONFIG_CPU_FREQ + /* In some cases the CPU can change frequency without us noticing + (like going into thermal throttle) + Give cpufreq a change to catch up. */ + if ((lost_count+1) % 25 == 0) { + cpufreq_delayed_get(); + } +#endif +} + +static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs) +{ + static unsigned long rtc_update = 0; + unsigned long tsc; + int delay, offset = 0, lost = 0; + +/* + * Here we are in the timer irq handler. We have irqs locally disabled (so we + * don't need spin_lock_irqsave()) but we don't know if the timer_bh is running + * on the other CPU, so we need a lock. We also need to lock the vsyscall + * variables, because both do_timer() and us change them -arca+vojtech + */ + + write_seqlock(&xtime_lock); + + if (vxtime.hpet_address) { + offset = hpet_readl(HPET_T0_CMP) - hpet_tick; + delay = hpet_readl(HPET_COUNTER) - offset; + } else { + spin_lock(&i8253_lock); + outb_p(0x00, 0x43); + delay = inb_p(0x40); + delay |= inb(0x40) << 8; + spin_unlock(&i8253_lock); + delay = LATCH - 1 - delay; + } + + rdtscll_sync(&tsc); + + if (vxtime.mode == VXTIME_HPET) { + if (offset - vxtime.last > hpet_tick) { + lost = (offset - vxtime.last) / hpet_tick - 1; + } + + monotonic_base += + (offset - vxtime.last)*(NSEC_PER_SEC/HZ) / hpet_tick; + + vxtime.last = offset; + } else { + offset = (((tsc - vxtime.last_tsc) * + vxtime.tsc_quot) >> 32) - (USEC_PER_SEC / HZ); + + if (offset < 0) + offset = 0; + + if (offset > (USEC_PER_SEC / HZ)) { + lost = offset / (USEC_PER_SEC / HZ); + offset %= (USEC_PER_SEC / HZ); + } + + monotonic_base += (tsc - vxtime.last_tsc)*1000000/cpu_khz ; + + vxtime.last_tsc = tsc - vxtime.quot * delay / vxtime.tsc_quot; + + if ((((tsc - vxtime.last_tsc) * + vxtime.tsc_quot) >> 32) < offset) + vxtime.last_tsc = tsc - + (((long) offset << 32) / vxtime.tsc_quot) - 1; + } + + if (lost > 0) { + handle_lost_ticks(lost, regs); + jiffies += lost; + } + +/* + * Do the timer stuff. + */ + + do_timer(regs); +#ifndef CONFIG_SMP + update_process_times(user_mode(regs)); +#endif + +/* + * In the SMP case we use the local APIC timer interrupt to do the profiling, + * except when we simulate SMP mode on a uniprocessor system, in that case we + * have to call the local interrupt handler. + */ + +#ifndef CONFIG_X86_LOCAL_APIC + profile_tick(CPU_PROFILING, regs); +#else + if (!using_apic_timer) + smp_local_timer_interrupt(regs); +#endif + +/* + * If we have an externally synchronized Linux clock, then update CMOS clock + * accordingly every ~11 minutes. set_rtc_mmss() will be called in the jiffy + * closest to exactly 500 ms before the next second. If the update fails, we + * don't care, as it'll be updated on the next turn, and the problem (time way + * off) isn't likely to go away much sooner anyway. + */ + + if ((~time_status & STA_UNSYNC) && xtime.tv_sec > rtc_update && + abs(xtime.tv_nsec - 500000000) <= tick_nsec / 2) { + set_rtc_mmss(xtime.tv_sec); + rtc_update = xtime.tv_sec + 660; + } + + write_sequnlock(&xtime_lock); + + return IRQ_HANDLED; +} + +static unsigned int cyc2ns_scale; +#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ + +static inline void set_cyc2ns_scale(unsigned long cpu_mhz) +{ + cyc2ns_scale = (1000 << CYC2NS_SCALE_FACTOR)/cpu_mhz; +} + +static inline unsigned long long cycles_2_ns(unsigned long long cyc) +{ + return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR; +} + +unsigned long long sched_clock(void) +{ + unsigned long a = 0; + +#if 0 + /* Don't do a HPET read here. Using TSC always is much faster + and HPET may not be mapped yet when the scheduler first runs. + Disadvantage is a small drift between CPUs in some configurations, + but that should be tolerable. */ + if (__vxtime.mode == VXTIME_HPET) + return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> 32; +#endif + + /* Could do CPU core sync here. Opteron can execute rdtsc speculatively, + which means it is not completely exact and may not be monotonous between + CPUs. But the errors should be too small to matter for scheduling + purposes. */ + + rdtscll(a); + return cycles_2_ns(a); +} + +unsigned long get_cmos_time(void) +{ + unsigned int timeout, year, mon, day, hour, min, sec; + unsigned char last, this; + unsigned long flags; + +/* + * The Linux interpretation of the CMOS clock register contents: When the + * Update-In-Progress (UIP) flag goes from 1 to 0, the RTC registers show the + * second which has precisely just started. Waiting for this can take up to 1 + * second, we timeout approximately after 2.4 seconds on a machine with + * standard 8.3 MHz ISA bus. + */ + + spin_lock_irqsave(&rtc_lock, flags); + + timeout = 1000000; + last = this = 0; + + while (timeout && last && !this) { + last = this; + this = CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP; + timeout--; + } + +/* + * Here we are safe to assume the registers won't change for a whole second, so + * we just go ahead and read them. + */ + + sec = CMOS_READ(RTC_SECONDS); + min = CMOS_READ(RTC_MINUTES); + hour = CMOS_READ(RTC_HOURS); + day = CMOS_READ(RTC_DAY_OF_MONTH); + mon = CMOS_READ(RTC_MONTH); + year = CMOS_READ(RTC_YEAR); + + spin_unlock_irqrestore(&rtc_lock, flags); + +/* + * We know that x86-64 always uses BCD format, no need to check the config + * register. + */ + + BCD_TO_BIN(sec); + BCD_TO_BIN(min); + BCD_TO_BIN(hour); + BCD_TO_BIN(day); + BCD_TO_BIN(mon); + BCD_TO_BIN(year); + +/* + * x86-64 systems only exists since 2002. + * This will work up to Dec 31, 2100 + */ + year += 2000; + + return mktime(year, mon, day, hour, min, sec); +} + +#ifdef CONFIG_CPU_FREQ + +/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency + changes. + + RED-PEN: On SMP we assume all CPUs run with the same frequency. It's + not that important because current Opteron setups do not support + scaling on SMP anyroads. + + Should fix up last_tsc too. Currently gettimeofday in the + first tick after the change will be slightly wrong. */ + +#include <linux/workqueue.h> + +static unsigned int cpufreq_delayed_issched = 0; +static unsigned int cpufreq_init = 0; +static struct work_struct cpufreq_delayed_get_work; + +static void handle_cpufreq_delayed_get(void *v) +{ + unsigned int cpu; + for_each_online_cpu(cpu) { + cpufreq_get(cpu); + } + cpufreq_delayed_issched = 0; +} + +/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries + * to verify the CPU frequency the timing core thinks the CPU is running + * at is still correct. + */ +static void cpufreq_delayed_get(void) +{ + static int warned; + if (cpufreq_init && !cpufreq_delayed_issched) { + cpufreq_delayed_issched = 1; + if (!warned) { + warned = 1; + printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n"); + } + schedule_work(&cpufreq_delayed_get_work); + } +} + +static unsigned int ref_freq = 0; +static unsigned long loops_per_jiffy_ref = 0; + +static unsigned long cpu_khz_ref = 0; + +static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct cpufreq_freqs *freq = data; + unsigned long *lpj, dummy; + + lpj = &dummy; + if (!(freq->flags & CPUFREQ_CONST_LOOPS)) +#ifdef CONFIG_SMP + lpj = &cpu_data[freq->cpu].loops_per_jiffy; +#else + lpj = &boot_cpu_data.loops_per_jiffy; +#endif + + + + if (!ref_freq) { + ref_freq = freq->old; + loops_per_jiffy_ref = *lpj; + cpu_khz_ref = cpu_khz; + } + if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) || + (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) || + (val == CPUFREQ_RESUMECHANGE)) { + *lpj = + cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new); + + cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new); + if (!(freq->flags & CPUFREQ_CONST_LOOPS)) + vxtime.tsc_quot = (1000L << 32) / cpu_khz; + } + + set_cyc2ns_scale(cpu_khz_ref / 1000); + + return 0; +} + +static struct notifier_block time_cpufreq_notifier_block = { + .notifier_call = time_cpufreq_notifier +}; + +static int __init cpufreq_tsc(void) +{ + INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL); + if (!cpufreq_register_notifier(&time_cpufreq_notifier_block, + CPUFREQ_TRANSITION_NOTIFIER)) + cpufreq_init = 1; + return 0; +} + +core_initcall(cpufreq_tsc); + +#endif + +/* + * calibrate_tsc() calibrates the processor TSC in a very simple way, comparing + * it to the HPET timer of known frequency. + */ + +#define TICK_COUNT 100000000 + +static unsigned int __init hpet_calibrate_tsc(void) +{ + int tsc_start, hpet_start; + int tsc_now, hpet_now; + unsigned long flags; + + local_irq_save(flags); + local_irq_disable(); + + hpet_start = hpet_readl(HPET_COUNTER); + rdtscl(tsc_start); + + do { + local_irq_disable(); + hpet_now = hpet_readl(HPET_COUNTER); + sync_core(); + rdtscl(tsc_now); + local_irq_restore(flags); + } while ((tsc_now - tsc_start) < TICK_COUNT && + (hpet_now - hpet_start) < TICK_COUNT); + + return (tsc_now - tsc_start) * 1000000000L + / ((hpet_now - hpet_start) * hpet_period / 1000); +} + + +/* + * pit_calibrate_tsc() uses the speaker output (channel 2) of + * the PIT. This is better than using the timer interrupt output, + * because we can read the value of the speaker with just one inb(), + * where we need three i/o operations for the interrupt channel. + * We count how many ticks the TSC does in 50 ms. + */ + +static unsigned int __init pit_calibrate_tsc(void) +{ + unsigned long start, end; + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + + outb((inb(0x61) & ~0x02) | 0x01, 0x61); + + outb(0xb0, 0x43); + outb((PIT_TICK_RATE / (1000 / 50)) & 0xff, 0x42); + outb((PIT_TICK_RATE / (1000 / 50)) >> 8, 0x42); + rdtscll(start); + sync_core(); + while ((inb(0x61) & 0x20) == 0); + sync_core(); + rdtscll(end); + + spin_unlock_irqrestore(&i8253_lock, flags); + + return (end - start) / 50; +} + +#ifdef CONFIG_HPET +static __init int late_hpet_init(void) +{ + struct hpet_data hd; + unsigned int ntimer; + + if (!vxtime.hpet_address) + return -1; + + memset(&hd, 0, sizeof (hd)); + + ntimer = hpet_readl(HPET_ID); + ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT; + ntimer++; + + /* + * Register with driver. + * Timer0 and Timer1 is used by platform. + */ + hd.hd_phys_address = vxtime.hpet_address; + hd.hd_address = (void *)fix_to_virt(FIX_HPET_BASE); + hd.hd_nirqs = ntimer; + hd.hd_flags = HPET_DATA_PLATFORM; + hpet_reserve_timer(&hd, 0); +#ifdef CONFIG_HPET_EMULATE_RTC + hpet_reserve_timer(&hd, 1); +#endif + hd.hd_irq[0] = HPET_LEGACY_8254; + hd.hd_irq[1] = HPET_LEGACY_RTC; + if (ntimer > 2) { + struct hpet *hpet; + struct hpet_timer *timer; + int i; + + hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE); + + for (i = 2, timer = &hpet->hpet_timers[2]; i < ntimer; + timer++, i++) + hd.hd_irq[i] = (timer->hpet_config & + Tn_INT_ROUTE_CNF_MASK) >> + Tn_INT_ROUTE_CNF_SHIFT; + + } + + hpet_alloc(&hd); + return 0; +} +fs_initcall(late_hpet_init); +#endif + +static int hpet_timer_stop_set_go(unsigned long tick) +{ + unsigned int cfg; + +/* + * Stop the timers and reset the main counter. + */ + + cfg = hpet_readl(HPET_CFG); + cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY); + hpet_writel(cfg, HPET_CFG); + hpet_writel(0, HPET_COUNTER); + hpet_writel(0, HPET_COUNTER + 4); + +/* + * Set up timer 0, as periodic with first interrupt to happen at hpet_tick, + * and period also hpet_tick. + */ + + hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL | + HPET_TN_32BIT, HPET_T0_CFG); + hpet_writel(hpet_tick, HPET_T0_CMP); + hpet_writel(hpet_tick, HPET_T0_CMP); /* AK: why twice? */ + +/* + * Go! + */ + + cfg |= HPET_CFG_ENABLE | HPET_CFG_LEGACY; + hpet_writel(cfg, HPET_CFG); + + return 0; +} + +static int hpet_init(void) +{ + unsigned int id; + + if (!vxtime.hpet_address) + return -1; + set_fixmap_nocache(FIX_HPET_BASE, vxtime.hpet_address); + __set_fixmap(VSYSCALL_HPET, vxtime.hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE); + +/* + * Read the period, compute tick and quotient. + */ + + id = hpet_readl(HPET_ID); + + if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER) || + !(id & HPET_ID_LEGSUP)) + return -1; + + hpet_period = hpet_readl(HPET_PERIOD); + if (hpet_period < 100000 || hpet_period > 100000000) + return -1; + + hpet_tick = (1000000000L * (USEC_PER_SEC / HZ) + hpet_period / 2) / + hpet_period; + + return hpet_timer_stop_set_go(hpet_tick); +} + +static int hpet_reenable(void) +{ + return hpet_timer_stop_set_go(hpet_tick); +} + +void __init pit_init(void) +{ + unsigned long flags; + + spin_lock_irqsave(&i8253_lock, flags); + outb_p(0x34, 0x43); /* binary, mode 2, LSB/MSB, ch 0 */ + outb_p(LATCH & 0xff, 0x40); /* LSB */ + outb_p(LATCH >> 8, 0x40); /* MSB */ + spin_unlock_irqrestore(&i8253_lock, flags); +} + +int __init time_setup(char *str) +{ + report_lost_ticks = 1; + return 1; +} + +static struct irqaction irq0 = { + timer_interrupt, SA_INTERRUPT, CPU_MASK_NONE, "timer", NULL, NULL +}; + +extern void __init config_acpi_tables(void); + +void __init time_init(void) +{ + char *timename; + +#ifdef HPET_HACK_ENABLE_DANGEROUS + if (!vxtime.hpet_address) { + printk(KERN_WARNING "time.c: WARNING: Enabling HPET base " + "manually!\n"); + outl(0x800038a0, 0xcf8); + outl(0xff000001, 0xcfc); + outl(0x800038a0, 0xcf8); + vxtime.hpet_address = inl(0xcfc) & 0xfffffffe; + printk(KERN_WARNING "time.c: WARNING: Enabled HPET " + "at %#lx.\n", vxtime.hpet_address); + } +#endif + if (nohpet) + vxtime.hpet_address = 0; + + xtime.tv_sec = get_cmos_time(); + xtime.tv_nsec = 0; + + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + + if (!hpet_init()) { + vxtime_hz = (1000000000000000L + hpet_period / 2) / + hpet_period; + cpu_khz = hpet_calibrate_tsc(); + timename = "HPET"; + } else { + pit_init(); + cpu_khz = pit_calibrate_tsc(); + timename = "PIT"; + } + + printk(KERN_INFO "time.c: Using %ld.%06ld MHz %s timer.\n", + vxtime_hz / 1000000, vxtime_hz % 1000000, timename); + printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n", + cpu_khz / 1000, cpu_khz % 1000); + vxtime.mode = VXTIME_TSC; + vxtime.quot = (1000000L << 32) / vxtime_hz; + vxtime.tsc_quot = (1000L << 32) / cpu_khz; + vxtime.hz = vxtime_hz; + rdtscll_sync(&vxtime.last_tsc); + setup_irq(0, &irq0); + + set_cyc2ns_scale(cpu_khz / 1000); +} + +void __init time_init_smp(void) +{ + char *timetype; + + /* + * AMD systems with more than one CPU don't have fully synchronized + * TSCs. Always use HPET gettimeofday for these, although it is slower. + * Intel SMP systems usually have synchronized TSCs, so use always + * the TSC. + * + * Exceptions: + * IBM Summit2 checked by oem_force_hpet_timer(). + * AMD dual core may also not need HPET. Check me. + * + * Can be turned off with "notsc". + */ + if (num_online_cpus() > 1 && + boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + notsc = 1; + /* Some systems will want to disable TSC and use HPET. */ + if (oem_force_hpet_timer()) + notsc = 1; + if (vxtime.hpet_address && notsc) { + timetype = "HPET"; + vxtime.last = hpet_readl(HPET_T0_CMP) - hpet_tick; + vxtime.mode = VXTIME_HPET; + do_gettimeoffset = do_gettimeoffset_hpet; + } else { + timetype = vxtime.hpet_address ? "HPET/TSC" : "PIT/TSC"; + vxtime.mode = VXTIME_TSC; + } + + printk(KERN_INFO "time.c: Using %s based timekeeping.\n", timetype); +} + +__setup("report_lost_ticks", time_setup); + +static long clock_cmos_diff; +static unsigned long sleep_start; + +static int timer_suspend(struct sys_device *dev, u32 state) +{ + /* + * Estimate time zone so that set_time can update the clock + */ + long cmos_time = get_cmos_time(); + + clock_cmos_diff = -cmos_time; + clock_cmos_diff += get_seconds(); + sleep_start = cmos_time; + return 0; +} + +static int timer_resume(struct sys_device *dev) +{ + unsigned long flags; + unsigned long sec; + unsigned long ctime = get_cmos_time(); + unsigned long sleep_length = (ctime - sleep_start) * HZ; + + if (vxtime.hpet_address) + hpet_reenable(); + else + i8254_timer_resume(); + + sec = ctime + clock_cmos_diff; + 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_EMULATE_RTC +/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET + * is enabled, we support RTC interrupt functionality in software. + * RTC has 3 kinds of interrupts: + * 1) Update Interrupt - generate an interrupt, every sec, when RTC clock + * is updated + * 2) Alarm Interrupt - generate an interrupt at a specific time of day + * 3) Periodic Interrupt - generate periodic interrupt, with frequencies + * 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2) + * (1) and (2) above are implemented using polling at a frequency of + * 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt + * overhead. (DEFAULT_RTC_INT_FREQ) + * For (3), we use interrupts at 64Hz or user specified periodic + * frequency, whichever is higher. + */ +#include <linux/rtc.h> + +extern irqreturn_t rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs); + +#define DEFAULT_RTC_INT_FREQ 64 +#define RTC_NUM_INTS 1 + +static unsigned long UIE_on; +static unsigned long prev_update_sec; + +static unsigned long AIE_on; +static struct rtc_time alarm_time; + +static unsigned long PIE_on; +static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ; +static unsigned long PIE_count; + +static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */ + +int is_hpet_enabled(void) +{ + return vxtime.hpet_address != 0; +} + +/* + * Timer 1 for RTC, we do not use periodic interrupt feature, + * even if HPET supports periodic interrupts on Timer 1. + * The reason being, to set up a periodic interrupt in HPET, we need to + * stop the main counter. And if we do that everytime someone diables/enables + * RTC, we will have adverse effect on main kernel timer running on Timer 0. + * So, for the time being, simulate the periodic interrupt in software. + * + * hpet_rtc_timer_init() is called for the first time and during subsequent + * interuppts reinit happens through hpet_rtc_timer_reinit(). + */ +int hpet_rtc_timer_init(void) +{ + unsigned int cfg, cnt; + unsigned long flags; + + if (!is_hpet_enabled()) + return 0; + /* + * Set the counter 1 and enable the interrupts. + */ + if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) + hpet_rtc_int_freq = PIE_freq; + else + hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; + + local_irq_save(flags); + cnt = hpet_readl(HPET_COUNTER); + cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq); + hpet_writel(cnt, HPET_T1_CMP); + local_irq_restore(flags); + + cfg = hpet_readl(HPET_T1_CFG); + cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT; + hpet_writel(cfg, HPET_T1_CFG); + + return 1; +} + +static void hpet_rtc_timer_reinit(void) +{ + unsigned int cfg, cnt; + + if (!(PIE_on | AIE_on | UIE_on)) + return; + + if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ)) + hpet_rtc_int_freq = PIE_freq; + else + hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ; + + /* It is more accurate to use the comparator value than current count.*/ + cnt = hpet_readl(HPET_T1_CMP); + cnt += hpet_tick*HZ/hpet_rtc_int_freq; + hpet_writel(cnt, HPET_T1_CMP); + + cfg = hpet_readl(HPET_T1_CFG); + cfg |= HPET_TN_ENABLE | HPET_TN_SETVAL | HPET_TN_32BIT; + hpet_writel(cfg, HPET_T1_CFG); + + return; +} + +/* + * The functions below are called from rtc driver. + * Return 0 if HPET is not being used. + * Otherwise do the necessary changes and return 1. + */ +int hpet_mask_rtc_irq_bit(unsigned long bit_mask) +{ + if (!is_hpet_enabled()) + return 0; + + if (bit_mask & RTC_UIE) + UIE_on = 0; + if (bit_mask & RTC_PIE) + PIE_on = 0; + if (bit_mask & RTC_AIE) + AIE_on = 0; + + return 1; +} + +int hpet_set_rtc_irq_bit(unsigned long bit_mask) +{ + int timer_init_reqd = 0; + + if (!is_hpet_enabled()) + return 0; + + if (!(PIE_on | AIE_on | UIE_on)) + timer_init_reqd = 1; + + if (bit_mask & RTC_UIE) { + UIE_on = 1; + } + if (bit_mask & RTC_PIE) { + PIE_on = 1; + PIE_count = 0; + } + if (bit_mask & RTC_AIE) { + AIE_on = 1; + } + + if (timer_init_reqd) + hpet_rtc_timer_init(); + + return 1; +} + +int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec) +{ + if (!is_hpet_enabled()) + return 0; + + alarm_time.tm_hour = hrs; + alarm_time.tm_min = min; + alarm_time.tm_sec = sec; + + return 1; +} + +int hpet_set_periodic_freq(unsigned long freq) +{ + if (!is_hpet_enabled()) + return 0; + + PIE_freq = freq; + PIE_count = 0; + + return 1; +} + +int hpet_rtc_dropped_irq(void) +{ + if (!is_hpet_enabled()) + return 0; + + return 1; +} + +irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs) +{ + struct rtc_time curr_time; + unsigned long rtc_int_flag = 0; + int call_rtc_interrupt = 0; + + hpet_rtc_timer_reinit(); + + if (UIE_on | AIE_on) { + rtc_get_rtc_time(&curr_time); + } + if (UIE_on) { + if (curr_time.tm_sec != prev_update_sec) { + /* Set update int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag = RTC_UF; + prev_update_sec = curr_time.tm_sec; + } + } + if (PIE_on) { + PIE_count++; + if (PIE_count >= hpet_rtc_int_freq/PIE_freq) { + /* Set periodic int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag |= RTC_PF; + PIE_count = 0; + } + } + if (AIE_on) { + if ((curr_time.tm_sec == alarm_time.tm_sec) && + (curr_time.tm_min == alarm_time.tm_min) && + (curr_time.tm_hour == alarm_time.tm_hour)) { + /* Set alarm int info, call real rtc int routine */ + call_rtc_interrupt = 1; + rtc_int_flag |= RTC_AF; + } + } + if (call_rtc_interrupt) { + rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8)); + rtc_interrupt(rtc_int_flag, dev_id, regs); + } + return IRQ_HANDLED; +} +#endif + + + +static int __init nohpet_setup(char *s) +{ + nohpet = 1; + return 0; +} + +__setup("nohpet", nohpet_setup); + + +static int __init notsc_setup(char *s) +{ + notsc = 1; + return 0; +} + +__setup("notsc", notsc_setup); + + |
