139 строки
3.4 KiB
C
139 строки
3.4 KiB
C
/*
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* "High Precision Event Timer" based timekeeping.
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*
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* Copyright (c) 1991,1992,1995 Linus Torvalds
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* Copyright (c) 1994 Alan Modra
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* Copyright (c) 1995 Markus Kuhn
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* Copyright (c) 1996 Ingo Molnar
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* Copyright (c) 1998 Andrea Arcangeli
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* Copyright (c) 2002,2006 Vojtech Pavlik
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* Copyright (c) 2003 Andi Kleen
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* RTC support code taken from arch/i386/kernel/timers/time_hpet.c
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*/
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#include <linux/clockchips.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/module.h>
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#include <linux/time.h>
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#include <asm/i8253.h>
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#include <asm/hpet.h>
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#include <asm/nmi.h>
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#include <asm/vgtod.h>
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#include <asm/time.h>
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#include <asm/timer.h>
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volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
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unsigned long profile_pc(struct pt_regs *regs)
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{
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unsigned long pc = instruction_pointer(regs);
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/* Assume the lock function has either no stack frame or a copy
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of flags from PUSHF
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Eflags always has bits 22 and up cleared unlike kernel addresses. */
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if (!user_mode(regs) && in_lock_functions(pc)) {
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unsigned long *sp = (unsigned long *)regs->sp;
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if (sp[0] >> 22)
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return sp[0];
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if (sp[1] >> 22)
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return sp[1];
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}
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return pc;
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}
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EXPORT_SYMBOL(profile_pc);
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static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
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{
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add_pda(irq0_irqs, 1);
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global_clock_event->event_handler(global_clock_event);
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return IRQ_HANDLED;
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}
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/* calibrate_cpu is used on systems with fixed rate TSCs to determine
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* processor frequency */
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#define TICK_COUNT 100000000
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unsigned long __init native_calculate_cpu_khz(void)
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{
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int tsc_start, tsc_now;
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int i, no_ctr_free;
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unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
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unsigned long flags;
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for (i = 0; i < 4; i++)
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if (avail_to_resrv_perfctr_nmi_bit(i))
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break;
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no_ctr_free = (i == 4);
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if (no_ctr_free) {
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i = 3;
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rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
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wrmsrl(MSR_K7_EVNTSEL3, 0);
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rdmsrl(MSR_K7_PERFCTR3, pmc3);
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} else {
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reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
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reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
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}
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local_irq_save(flags);
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/* start measuring cycles, incrementing from 0 */
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wrmsrl(MSR_K7_PERFCTR0 + i, 0);
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wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
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rdtscl(tsc_start);
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do {
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rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
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tsc_now = get_cycles();
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} while ((tsc_now - tsc_start) < TICK_COUNT);
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local_irq_restore(flags);
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if (no_ctr_free) {
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wrmsrl(MSR_K7_EVNTSEL3, 0);
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wrmsrl(MSR_K7_PERFCTR3, pmc3);
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wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
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} else {
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release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
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release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
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}
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return pmc_now * tsc_khz / (tsc_now - tsc_start);
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}
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static struct irqaction irq0 = {
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.handler = timer_event_interrupt,
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.flags = IRQF_DISABLED | IRQF_IRQPOLL | IRQF_NOBALANCING,
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.mask = CPU_MASK_NONE,
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.name = "timer"
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};
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void __init hpet_time_init(void)
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{
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if (!hpet_enable())
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setup_pit_timer();
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setup_irq(0, &irq0);
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}
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void __init time_init(void)
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{
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tsc_calibrate();
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cpu_khz = tsc_khz;
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if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
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(boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
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cpu_khz = calculate_cpu_khz();
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if (unsynchronized_tsc())
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mark_tsc_unstable("TSCs unsynchronized");
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if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
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vgetcpu_mode = VGETCPU_RDTSCP;
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else
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vgetcpu_mode = VGETCPU_LSL;
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printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
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cpu_khz / 1000, cpu_khz % 1000);
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init_tsc_clocksource();
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late_time_init = choose_time_init();
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}
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