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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
3 *
4 * This file contains the PC-specific time handling details:
5 * reading the RTC at bootup, etc..
6 * 1994-07-02 Alan Modra
7 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
8 * 1995-03-26 Markus Kuhn
9 * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
10 * precision CMOS clock update
11 * 1996-05-03 Ingo Molnar
12 * fixed time warps in do_[slow|fast]_gettimeoffset()
13 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
14 * "A Kernel Model for Precision Timekeeping" by Dave Mills
15 * 1998-09-05 (Various)
16 * More robust do_fast_gettimeoffset() algorithm implemented
17 * (works with APM, Cyrix 6x86MX and Centaur C6),
18 * monotonic gettimeofday() with fast_get_timeoffset(),
19 * drift-proof precision TSC calibration on boot
20 * (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
21 * Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
22 * ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
23 * 1998-12-16 Andrea Arcangeli
24 * Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
25 * because was not accounting lost_ticks.
26 * 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
27 * Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
28 * serialize accesses to xtime/lost_ticks).
29 */
30
Thomas Gleixnerfe599f92008-01-30 13:30:26 +010031#include <linux/init.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/interrupt.h>
33#include <linux/time.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/mca.h>
35
Ingo Molnar8e6dafd2009-02-23 00:34:39 +010036#include <asm/setup.h>
Thomas Gleixnerfe599f92008-01-30 13:30:26 +010037#include <asm/hpet.h>
Rusty Russelld3561b72006-12-07 02:14:07 +010038#include <asm/time.h>
Jaswinder Singhcc038492008-07-21 21:52:51 +053039#include <asm/timer.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
Ingo Molnar1164dd02009-01-28 19:34:09 +010041#include <asm/do_timer.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042
Linus Torvalds1da177e2005-04-16 15:20:36 -070043int timer_ack;
44
Linus Torvalds1da177e2005-04-16 15:20:36 -070045unsigned long profile_pc(struct pt_regs *regs)
46{
47 unsigned long pc = instruction_pointer(regs);
48
Andi Kleen0cb91a22006-09-26 10:52:28 +020049#ifdef CONFIG_SMP
Glauber Costa2c44e662008-07-11 13:48:07 -030050 if (!user_mode_vm(regs) && in_lock_functions(pc)) {
Andi Kleen0cb91a22006-09-26 10:52:28 +020051#ifdef CONFIG_FRAME_POINTER
Glauber Costa2c460d02008-07-11 16:06:40 -030052 return *(unsigned long *)(regs->bp + sizeof(long));
Andi Kleen0cb91a22006-09-26 10:52:28 +020053#else
H. Peter Anvin65ea5b02008-01-30 13:30:56 +010054 unsigned long *sp = (unsigned long *)&regs->sp;
Zachary Amsden7b355202007-02-13 13:26:21 +010055
Andi Kleen0cb91a22006-09-26 10:52:28 +020056 /* Return address is either directly at stack pointer
H. Peter Anvin65ea5b02008-01-30 13:30:56 +010057 or above a saved flags. Eflags has bits 22-31 zero,
Andi Kleen0cb91a22006-09-26 10:52:28 +020058 kernel addresses don't. */
Thomas Gleixnerfe599f92008-01-30 13:30:26 +010059 if (sp[0] >> 22)
Andi Kleen0cb91a22006-09-26 10:52:28 +020060 return sp[0];
61 if (sp[1] >> 22)
62 return sp[1];
63#endif
64 }
65#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 return pc;
67}
68EXPORT_SYMBOL(profile_pc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
70/*
john stultz6f84fa22006-06-26 00:25:11 -070071 * This is the same as the above, except we _also_ save the current
72 * Time Stamp Counter value at the time of the timer interrupt, so that
73 * we later on can estimate the time of day more exactly.
Linus Torvalds1da177e2005-04-16 15:20:36 -070074 */
David Howells7d12e782006-10-05 14:55:46 +010075irqreturn_t timer_interrupt(int irq, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -070076{
Thomas Gleixner3c9aea42007-10-12 23:04:06 +020077 /* Keep nmi watchdog up to date */
Hiroshi Shimamoto8ae93662008-12-12 15:52:26 -080078 inc_irq_stat(irq0_irqs);
Thomas Gleixner3c9aea42007-10-12 23:04:06 +020079
Linus Torvalds1da177e2005-04-16 15:20:36 -070080#ifdef CONFIG_X86_IO_APIC
81 if (timer_ack) {
82 /*
83 * Subtle, when I/O APICs are used we have to ack timer IRQ
Maciej W. Rozyckid11d5792008-05-21 22:09:11 +010084 * manually to deassert NMI lines for the watchdog if run
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 * on an 82489DX-based system.
86 */
87 spin_lock(&i8259A_lock);
88 outb(0x0c, PIC_MASTER_OCW3);
89 /* Ack the IRQ; AEOI will end it automatically. */
90 inb(PIC_MASTER_POLL);
91 spin_unlock(&i8259A_lock);
92 }
93#endif
94
David Howells7d12e782006-10-05 14:55:46 +010095 do_timer_interrupt_hook();
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
Glauber Costa33c053d2008-07-21 18:42:52 -030097#ifdef CONFIG_MCA
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 if (MCA_bus) {
99 /* The PS/2 uses level-triggered interrupts. You can't
100 turn them off, nor would you want to (any attempt to
101 enable edge-triggered interrupts usually gets intercepted by a
102 special hardware circuit). Hence we have to acknowledge
103 the timer interrupt. Through some incredibly stupid
104 design idea, the reset for IRQ 0 is done by setting the
105 high bit of the PPI port B (0x61). Note that some PS/2s,
106 notably the 55SX, work fine if this is removed. */
107
Jaswinder Singh Rajput69036c82009-01-04 16:26:52 +0530108 u8 irq_v = inb_p(0x61); /* read the current state */
109 outb_p(irq_v | 0x80, 0x61); /* reset the IRQ */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 }
Glauber Costa33c053d2008-07-21 18:42:52 -0300111#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 return IRQ_HANDLED;
114}
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116/* Duplicate of time_init() below, with hpet_enable part added */
Zachary Amsdene30fab32007-03-05 00:30:39 -0800117void __init hpet_time_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118{
Thomas Gleixnere9e2cdb2007-02-16 01:28:04 -0800119 if (!hpet_enable())
120 setup_pit_timer();
Ingo Molnar8e6dafd2009-02-23 00:34:39 +0100121 x86_quirk_time_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
Zachary Amsdene30fab32007-03-05 00:30:39 -0800124/*
125 * This is called directly from init code; we must delay timer setup in the
126 * HPET case as we can't make the decision to turn on HPET this early in the
127 * boot process.
128 *
129 * The chosen time_init function will usually be hpet_time_init, above, but
130 * in the case of virtual hardware, an alternative function may be substituted.
131 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132void __init time_init(void)
133{
Ingo Molnar8e6dafd2009-02-23 00:34:39 +0100134 x86_quirk_pre_time_init();
john stultz6bb74df2007-03-05 00:30:50 -0800135 tsc_init();
Zachary Amsdene30fab32007-03-05 00:30:39 -0800136 late_time_init = choose_time_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137}