2005-04-16 22:20:36 +00:00
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/*
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* Copyright (C) 1991, 1992, 1995 Linus Torvalds
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*
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* This file contains the PC-specific time handling details:
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* reading the RTC at bootup, etc..
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* 1994-07-02 Alan Modra
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* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
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* 1995-03-26 Markus Kuhn
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* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
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* precision CMOS clock update
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* 1996-05-03 Ingo Molnar
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* fixed time warps in do_[slow|fast]_gettimeoffset()
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* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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* 1998-09-05 (Various)
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* More robust do_fast_gettimeoffset() algorithm implemented
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* (works with APM, Cyrix 6x86MX and Centaur C6),
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* monotonic gettimeofday() with fast_get_timeoffset(),
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* drift-proof precision TSC calibration on boot
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* (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
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* Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
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* ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
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* 1998-12-16 Andrea Arcangeli
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* Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
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* because was not accounting lost_ticks.
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* 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
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* Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
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* serialize accesses to xtime/lost_ticks).
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*/
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2008-01-30 12:30:26 +00:00
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#include <linux/init.h>
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2005-04-16 22:20:36 +00:00
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#include <linux/interrupt.h>
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#include <linux/time.h>
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#include <linux/mca.h>
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#include <asm/arch_hooks.h>
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2008-01-30 12:30:26 +00:00
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#include <asm/hpet.h>
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#include <asm/time.h>
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2005-04-16 22:20:36 +00:00
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#include "do_timer.h"
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2005-06-23 07:08:34 +00:00
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unsigned int cpu_khz; /* Detected as we calibrate the TSC */
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2005-06-23 07:08:33 +00:00
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EXPORT_SYMBOL(cpu_khz);
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2005-04-16 22:20:36 +00:00
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int timer_ack;
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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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2006-09-26 08:52:28 +00:00
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#ifdef CONFIG_SMP
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2008-01-30 12:30:56 +00:00
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if (!v8086_mode(regs) && SEGMENT_IS_KERNEL_CODE(regs->cs) &&
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2007-02-13 12:26:21 +00:00
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in_lock_functions(pc)) {
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2006-09-26 08:52:28 +00:00
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#ifdef CONFIG_FRAME_POINTER
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2008-01-30 12:30:56 +00:00
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return *(unsigned long *)(regs->bp + 4);
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2006-09-26 08:52:28 +00:00
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#else
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2008-01-30 12:30:56 +00:00
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unsigned long *sp = (unsigned long *)®s->sp;
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2007-02-13 12:26:21 +00:00
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2006-09-26 08:52:28 +00:00
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/* Return address is either directly at stack pointer
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2008-01-30 12:30:56 +00:00
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or above a saved flags. Eflags has bits 22-31 zero,
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2006-09-26 08:52:28 +00:00
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kernel addresses don't. */
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2008-01-30 12:30:26 +00:00
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if (sp[0] >> 22)
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2006-09-26 08:52:28 +00:00
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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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#endif
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}
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#endif
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2005-04-16 22:20:36 +00:00
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return pc;
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}
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EXPORT_SYMBOL(profile_pc);
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/*
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2006-06-26 07:25:11 +00:00
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* This is the same as the above, except we _also_ save the current
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* Time Stamp Counter value at the time of the timer interrupt, so that
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* we later on can estimate the time of day more exactly.
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2005-04-16 22:20:36 +00:00
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*/
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IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
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irqreturn_t timer_interrupt(int irq, void *dev_id)
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2005-04-16 22:20:36 +00:00
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{
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2007-10-12 21:04:06 +00:00
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/* Keep nmi watchdog up to date */
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per_cpu(irq_stat, smp_processor_id()).irq0_irqs++;
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2005-04-16 22:20:36 +00:00
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#ifdef CONFIG_X86_IO_APIC
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if (timer_ack) {
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/*
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* Subtle, when I/O APICs are used we have to ack timer IRQ
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* manually to reset the IRR bit for do_slow_gettimeoffset().
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* This will also deassert NMI lines for the watchdog if run
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* on an 82489DX-based system.
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*/
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spin_lock(&i8259A_lock);
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outb(0x0c, PIC_MASTER_OCW3);
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/* Ack the IRQ; AEOI will end it automatically. */
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inb(PIC_MASTER_POLL);
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spin_unlock(&i8259A_lock);
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}
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#endif
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IRQ: Maintain regs pointer globally rather than passing to IRQ handlers
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.
The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around. On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).
Where appropriate, an arch may override the generic storage facility and do
something different with the variable. On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.
Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions. Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller. A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.
I've build this code with allyesconfig for x86_64 and i386. I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.
This will affect all archs. Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:
struct pt_regs *old_regs = set_irq_regs(regs);
And put the old one back at the end:
set_irq_regs(old_regs);
Don't pass regs through to generic_handle_irq() or __do_IRQ().
In timer_interrupt(), this sort of change will be necessary:
- update_process_times(user_mode(regs));
- profile_tick(CPU_PROFILING, regs);
+ update_process_times(user_mode(get_irq_regs()));
+ profile_tick(CPU_PROFILING);
I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().
Some notes on the interrupt handling in the drivers:
(*) input_dev() is now gone entirely. The regs pointer is no longer stored in
the input_dev struct.
(*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
something different depending on whether it's been supplied with a regs
pointer or not.
(*) Various IRQ handler function pointers have been moved to type
irq_handler_t.
Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 13:55:46 +00:00
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do_timer_interrupt_hook();
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2005-04-16 22:20:36 +00:00
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if (MCA_bus) {
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/* The PS/2 uses level-triggered interrupts. You can't
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turn them off, nor would you want to (any attempt to
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enable edge-triggered interrupts usually gets intercepted by a
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special hardware circuit). Hence we have to acknowledge
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the timer interrupt. Through some incredibly stupid
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design idea, the reset for IRQ 0 is done by setting the
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high bit of the PPI port B (0x61). Note that some PS/2s,
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notably the 55SX, work fine if this is removed. */
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2006-10-06 17:32:44 +00:00
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u8 irq_v = inb_p( 0x61 ); /* read the current state */
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outb_p( irq_v|0x80, 0x61 ); /* reset the IRQ */
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2005-04-16 22:20:36 +00:00
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}
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return IRQ_HANDLED;
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}
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/* Duplicate of time_init() below, with hpet_enable part added */
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2007-03-05 08:30:39 +00:00
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void __init hpet_time_init(void)
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2005-04-16 22:20:36 +00:00
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{
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2007-02-16 09:28:04 +00:00
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if (!hpet_enable())
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setup_pit_timer();
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2007-03-05 08:30:39 +00:00
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time_init_hook();
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2005-04-16 22:20:36 +00:00
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}
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2007-03-05 08:30:39 +00:00
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/*
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* This is called directly from init code; we must delay timer setup in the
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* HPET case as we can't make the decision to turn on HPET this early in the
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* boot process.
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*
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* The chosen time_init function will usually be hpet_time_init, above, but
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* in the case of virtual hardware, an alternative function may be substituted.
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*/
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2005-04-16 22:20:36 +00:00
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void __init time_init(void)
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{
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2007-03-05 08:30:50 +00:00
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tsc_init();
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2007-03-05 08:30:39 +00:00
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late_time_init = choose_time_init();
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2005-04-16 22:20:36 +00:00
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}
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