blob: 8a322c96bc23fdb9465e3b59e7d035b0094e0132 [file] [log] [blame]
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
31#include <linux/errno.h>
32#include <linux/sched.h>
33#include <linux/kernel.h>
34#include <linux/param.h>
35#include <linux/string.h>
36#include <linux/mm.h>
37#include <linux/interrupt.h>
38#include <linux/time.h>
39#include <linux/delay.h>
40#include <linux/init.h>
41#include <linux/smp.h>
42#include <linux/module.h>
43#include <linux/sysdev.h>
44#include <linux/bcd.h>
45#include <linux/efi.h>
46#include <linux/mca.h>
47
48#include <asm/io.h>
49#include <asm/smp.h>
50#include <asm/irq.h>
51#include <asm/msr.h>
52#include <asm/delay.h>
53#include <asm/mpspec.h>
54#include <asm/uaccess.h>
55#include <asm/processor.h>
56#include <asm/timer.h>
Rusty Russelld3561b72006-12-07 02:14:07 +010057#include <asm/time.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
59#include "mach_time.h"
60
61#include <linux/timex.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63#include <asm/hpet.h>
64
65#include <asm/arch_hooks.h>
66
67#include "io_ports.h"
68
Ingo Molnar306e4402005-06-30 02:58:55 -070069#include <asm/i8259.h>
70
Linus Torvalds1da177e2005-04-16 15:20:36 -070071#include "do_timer.h"
72
Andrew Mortona3a255e2005-06-23 00:08:34 -070073unsigned int cpu_khz; /* Detected as we calibrate the TSC */
Alexey Dobriyan129f6942005-06-23 00:08:33 -070074EXPORT_SYMBOL(cpu_khz);
Linus Torvalds1da177e2005-04-16 15:20:36 -070075
Linus Torvalds1da177e2005-04-16 15:20:36 -070076DEFINE_SPINLOCK(rtc_lock);
Alexey Dobriyan129f6942005-06-23 00:08:33 -070077EXPORT_SYMBOL(rtc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070078
Linus Torvalds1da177e2005-04-16 15:20:36 -070079/*
80 * This is a special lock that is owned by the CPU and holds the index
81 * register we are working with. It is required for NMI access to the
82 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
83 */
84volatile unsigned long cmos_lock = 0;
85EXPORT_SYMBOL(cmos_lock);
86
87/* Routines for accessing the CMOS RAM/RTC. */
88unsigned char rtc_cmos_read(unsigned char addr)
89{
90 unsigned char val;
91 lock_cmos_prefix(addr);
92 outb_p(addr, RTC_PORT(0));
93 val = inb_p(RTC_PORT(1));
94 lock_cmos_suffix(addr);
95 return val;
96}
97EXPORT_SYMBOL(rtc_cmos_read);
98
99void rtc_cmos_write(unsigned char val, unsigned char addr)
100{
101 lock_cmos_prefix(addr);
102 outb_p(addr, RTC_PORT(0));
103 outb_p(val, RTC_PORT(1));
104 lock_cmos_suffix(addr);
105}
106EXPORT_SYMBOL(rtc_cmos_write);
107
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108static int set_rtc_mmss(unsigned long nowtime)
109{
110 int retval;
john stultz6f84fa22006-06-26 00:25:11 -0700111 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112
113 /* gets recalled with irq locally disabled */
john stultz6f84fa22006-06-26 00:25:11 -0700114 /* XXX - does irqsave resolve this? -johnstul */
115 spin_lock_irqsave(&rtc_lock, flags);
Rusty Russelld3561b72006-12-07 02:14:07 +0100116 retval = set_wallclock(nowtime);
john stultz6f84fa22006-06-26 00:25:11 -0700117 spin_unlock_irqrestore(&rtc_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700118
119 return retval;
120}
121
122
123int timer_ack;
124
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125unsigned long profile_pc(struct pt_regs *regs)
126{
127 unsigned long pc = instruction_pointer(regs);
128
Andi Kleen0cb91a22006-09-26 10:52:28 +0200129#ifdef CONFIG_SMP
Zachary Amsden7b355202007-02-13 13:26:21 +0100130 if (!v8086_mode(regs) && SEGMENT_IS_KERNEL_CODE(regs->xcs) &&
131 in_lock_functions(pc)) {
Andi Kleen0cb91a22006-09-26 10:52:28 +0200132#ifdef CONFIG_FRAME_POINTER
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 return *(unsigned long *)(regs->ebp + 4);
Andi Kleen0cb91a22006-09-26 10:52:28 +0200134#else
Zachary Amsden7b355202007-02-13 13:26:21 +0100135 unsigned long *sp = (unsigned long *)&regs->esp;
136
Andi Kleen0cb91a22006-09-26 10:52:28 +0200137 /* Return address is either directly at stack pointer
138 or above a saved eflags. Eflags has bits 22-31 zero,
139 kernel addresses don't. */
140 if (sp[0] >> 22)
141 return sp[0];
142 if (sp[1] >> 22)
143 return sp[1];
144#endif
145 }
146#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 return pc;
148}
149EXPORT_SYMBOL(profile_pc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150
151/*
john stultz6f84fa22006-06-26 00:25:11 -0700152 * This is the same as the above, except we _also_ save the current
153 * Time Stamp Counter value at the time of the timer interrupt, so that
154 * we later on can estimate the time of day more exactly.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 */
David Howells7d12e782006-10-05 14:55:46 +0100156irqreturn_t timer_interrupt(int irq, void *dev_id)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157{
Thomas Gleixner3c9aea42007-10-12 23:04:06 +0200158 /* Keep nmi watchdog up to date */
159 per_cpu(irq_stat, smp_processor_id()).irq0_irqs++;
160
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161#ifdef CONFIG_X86_IO_APIC
162 if (timer_ack) {
163 /*
164 * Subtle, when I/O APICs are used we have to ack timer IRQ
165 * manually to reset the IRR bit for do_slow_gettimeoffset().
166 * This will also deassert NMI lines for the watchdog if run
167 * on an 82489DX-based system.
168 */
169 spin_lock(&i8259A_lock);
170 outb(0x0c, PIC_MASTER_OCW3);
171 /* Ack the IRQ; AEOI will end it automatically. */
172 inb(PIC_MASTER_POLL);
173 spin_unlock(&i8259A_lock);
174 }
175#endif
176
David Howells7d12e782006-10-05 14:55:46 +0100177 do_timer_interrupt_hook();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 if (MCA_bus) {
180 /* The PS/2 uses level-triggered interrupts. You can't
181 turn them off, nor would you want to (any attempt to
182 enable edge-triggered interrupts usually gets intercepted by a
183 special hardware circuit). Hence we have to acknowledge
184 the timer interrupt. Through some incredibly stupid
185 design idea, the reset for IRQ 0 is done by setting the
186 high bit of the PPI port B (0x61). Note that some PS/2s,
187 notably the 55SX, work fine if this is removed. */
188
Jeff Garzik86d91ba2006-10-06 13:32:44 -0400189 u8 irq_v = inb_p( 0x61 ); /* read the current state */
190 outb_p( irq_v|0x80, 0x61 ); /* reset the IRQ */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 return IRQ_HANDLED;
194}
195
196/* not static: needed by APM */
John Stultzc1d370e2007-02-16 01:27:31 -0800197unsigned long read_persistent_clock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198{
199 unsigned long retval;
Andrew Morton7ba1c6c2006-07-10 04:44:59 -0700200 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Andrew Morton7ba1c6c2006-07-10 04:44:59 -0700202 spin_lock_irqsave(&rtc_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
Rusty Russelld3561b72006-12-07 02:14:07 +0100204 retval = get_wallclock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700205
Andrew Morton7ba1c6c2006-07-10 04:44:59 -0700206 spin_unlock_irqrestore(&rtc_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207
208 return retval;
209}
Alexey Dobriyan129f6942005-06-23 00:08:33 -0700210
Thomas Gleixner82644452007-07-21 04:37:37 -0700211int update_persistent_clock(struct timespec now)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212{
Thomas Gleixner82644452007-07-21 04:37:37 -0700213 return set_rtc_mmss(now.tv_sec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214}
215
Linus Torvalds1e4c85f2005-10-31 19:16:17 -0800216extern void (*late_time_init)(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700217/* Duplicate of time_init() below, with hpet_enable part added */
Zachary Amsdene30fab32007-03-05 00:30:39 -0800218void __init hpet_time_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
Thomas Gleixnere9e2cdb2007-02-16 01:28:04 -0800220 if (!hpet_enable())
221 setup_pit_timer();
Zachary Amsdene30fab32007-03-05 00:30:39 -0800222 time_init_hook();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Zachary Amsdene30fab32007-03-05 00:30:39 -0800225/*
226 * This is called directly from init code; we must delay timer setup in the
227 * HPET case as we can't make the decision to turn on HPET this early in the
228 * boot process.
229 *
230 * The chosen time_init function will usually be hpet_time_init, above, but
231 * in the case of virtual hardware, an alternative function may be substituted.
232 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233void __init time_init(void)
234{
john stultz6bb74df2007-03-05 00:30:50 -0800235 tsc_init();
Zachary Amsdene30fab32007-03-05 00:30:39 -0800236 late_time_init = choose_time_init();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237}