| /* | |
| * 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 <cananian@alumni.princeton.edu>, Andrew D. | |
| * Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>; | |
| * ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>). | |
| * 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 <linux/init.h> | |
| #include <linux/interrupt.h> | |
| #include <linux/time.h> | |
| #include <linux/mca.h> | |
| #include <asm/arch_hooks.h> | |
| #include <asm/hpet.h> | |
| #include <asm/time.h> | |
| #include "do_timer.h" | |
| unsigned int cpu_khz; /* Detected as we calibrate the TSC */ | |
| EXPORT_SYMBOL(cpu_khz); | |
| int timer_ack; | |
| unsigned long profile_pc(struct pt_regs *regs) | |
| { | |
| unsigned long pc = instruction_pointer(regs); | |
| #ifdef CONFIG_SMP | |
| if (!v8086_mode(regs) && SEGMENT_IS_KERNEL_CODE(regs->cs) && | |
| in_lock_functions(pc)) { | |
| #ifdef CONFIG_FRAME_POINTER | |
| return *(unsigned long *)(regs->bp + 4); | |
| #else | |
| unsigned long *sp = (unsigned long *)®s->sp; | |
| /* Return address is either directly at stack pointer | |
| or above a saved flags. Eflags has bits 22-31 zero, | |
| kernel addresses don't. */ | |
| if (sp[0] >> 22) | |
| return sp[0]; | |
| if (sp[1] >> 22) | |
| return sp[1]; | |
| #endif | |
| } | |
| #endif | |
| return pc; | |
| } | |
| EXPORT_SYMBOL(profile_pc); | |
| /* | |
| * 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) | |
| { | |
| /* Keep nmi watchdog up to date */ | |
| per_cpu(irq_stat, smp_processor_id()).irq0_irqs++; | |
| #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(); | |
| 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. */ | |
| u8 irq_v = inb_p( 0x61 ); /* read the current state */ | |
| outb_p( irq_v|0x80, 0x61 ); /* reset the IRQ */ | |
| } | |
| return IRQ_HANDLED; | |
| } | |
| /* Duplicate of time_init() below, with hpet_enable part added */ | |
| void __init hpet_time_init(void) | |
| { | |
| if (!hpet_enable()) | |
| setup_pit_timer(); | |
| time_init_hook(); | |
| } | |
| /* | |
| * This is called directly from init code; we must delay timer setup in the | |
| * HPET case as we can't make the decision to turn on HPET this early in the | |
| * boot process. | |
| * | |
| * The chosen time_init function will usually be hpet_time_init, above, but | |
| * in the case of virtual hardware, an alternative function may be substituted. | |
| */ | |
| void __init time_init(void) | |
| { | |
| tsc_init(); | |
| late_time_init = choose_time_init(); | |
| } |