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1/*
2 * linux/arch/i386/kernel/time.c
3 *
4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
5 *
6 * This file contains the PC-specific time handling details:
7 * reading the RTC at bootup, etc..
8 * 1994-07-02 Alan Modra
9 * fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
10 * 1995-03-26 Markus Kuhn
11 * fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
12 * precision CMOS clock update
13 * 1996-05-03 Ingo Molnar
14 * fixed time warps in do_[slow|fast]_gettimeoffset()
15 * 1997-09-10 Updated NTP code according to technical memorandum Jan '96
16 * "A Kernel Model for Precision Timekeeping" by Dave Mills
17 * 1998-09-05 (Various)
18 * More robust do_fast_gettimeoffset() algorithm implemented
19 * (works with APM, Cyrix 6x86MX and Centaur C6),
20 * monotonic gettimeofday() with fast_get_timeoffset(),
21 * drift-proof precision TSC calibration on boot
22 * (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
23 * Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
24 * ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
25 * 1998-12-16 Andrea Arcangeli
26 * Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
27 * because was not accounting lost_ticks.
28 * 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
29 * Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
30 * serialize accesses to xtime/lost_ticks).
31 */
32
33#include <linux/errno.h>
34#include <linux/sched.h>
35#include <linux/kernel.h>
36#include <linux/param.h>
37#include <linux/string.h>
38#include <linux/mm.h>
39#include <linux/interrupt.h>
40#include <linux/time.h>
41#include <linux/delay.h>
42#include <linux/init.h>
43#include <linux/smp.h>
44#include <linux/module.h>
45#include <linux/sysdev.h>
46#include <linux/bcd.h>
47#include <linux/efi.h>
48#include <linux/mca.h>
49
50#include <asm/io.h>
51#include <asm/smp.h>
52#include <asm/irq.h>
53#include <asm/msr.h>
54#include <asm/delay.h>
55#include <asm/mpspec.h>
56#include <asm/uaccess.h>
57#include <asm/processor.h>
58#include <asm/timer.h>
59#include <asm/time.h>
60
61#include "mach_time.h"
62
63#include <linux/timex.h>
64
65#include <asm/hpet.h>
66
67#include <asm/arch_hooks.h>
68
69#include "io_ports.h"
70
71#include <asm/i8259.h>
72
73#include "do_timer.h"
74
75unsigned int cpu_khz; /* Detected as we calibrate the TSC */
76EXPORT_SYMBOL(cpu_khz);
77
78DEFINE_SPINLOCK(rtc_lock);
79EXPORT_SYMBOL(rtc_lock);
80
81/*
82 * This is a special lock that is owned by the CPU and holds the index
83 * register we are working with. It is required for NMI access to the
84 * CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
85 */
86volatile unsigned long cmos_lock = 0;
87EXPORT_SYMBOL(cmos_lock);
88
89/* Routines for accessing the CMOS RAM/RTC. */
90unsigned char rtc_cmos_read(unsigned char addr)
91{
92 unsigned char val;
93 lock_cmos_prefix(addr);
94 outb_p(addr, RTC_PORT(0));
95 val = inb_p(RTC_PORT(1));
96 lock_cmos_suffix(addr);
97 return val;
98}
99EXPORT_SYMBOL(rtc_cmos_read);
100
101void rtc_cmos_write(unsigned char val, unsigned char addr)
102{
103 lock_cmos_prefix(addr);
104 outb_p(addr, RTC_PORT(0));
105 outb_p(val, RTC_PORT(1));
106 lock_cmos_suffix(addr);
107}
108EXPORT_SYMBOL(rtc_cmos_write);
109
110static int set_rtc_mmss(unsigned long nowtime)
111{
112 int retval;
113 unsigned long flags;
114
115 /* gets recalled with irq locally disabled */
116 /* XXX - does irqsave resolve this? -johnstul */
117 spin_lock_irqsave(&rtc_lock, flags);
118 retval = set_wallclock(nowtime);
119 spin_unlock_irqrestore(&rtc_lock, flags);
120
121 return retval;
122}
123
124
125int timer_ack;
126
127unsigned long profile_pc(struct pt_regs *regs)
128{
129 unsigned long pc = instruction_pointer(regs);
130
131#ifdef CONFIG_SMP
132 if (!v8086_mode(regs) && SEGMENT_IS_KERNEL_CODE(regs->xcs) &&
133 in_lock_functions(pc)) {
134#ifdef CONFIG_FRAME_POINTER
135 return *(unsigned long *)(regs->ebp + 4);
136#else
137 unsigned long *sp = (unsigned long *)&regs->esp;
138
139 /* Return address is either directly at stack pointer
140 or above a saved eflags. Eflags has bits 22-31 zero,
141 kernel addresses don't. */
142 if (sp[0] >> 22)
143 return sp[0];
144 if (sp[1] >> 22)
145 return sp[1];
146#endif
147 }
148#endif
149 return pc;
150}
151EXPORT_SYMBOL(profile_pc);
152
153/*
154 * This is the same as the above, except we _also_ save the current
155 * Time Stamp Counter value at the time of the timer interrupt, so that
156 * we later on can estimate the time of day more exactly.
157 */
158irqreturn_t timer_interrupt(int irq, void *dev_id)
159{
160#ifdef CONFIG_X86_IO_APIC
161 if (timer_ack) {
162 /*
163 * Subtle, when I/O APICs are used we have to ack timer IRQ
164 * manually to reset the IRR bit for do_slow_gettimeoffset().
165 * This will also deassert NMI lines for the watchdog if run
166 * on an 82489DX-based system.
167 */
168 spin_lock(&i8259A_lock);
169 outb(0x0c, PIC_MASTER_OCW3);
170 /* Ack the IRQ; AEOI will end it automatically. */
171 inb(PIC_MASTER_POLL);
172 spin_unlock(&i8259A_lock);
173 }
174#endif
175
176 do_timer_interrupt_hook();
177
178 if (MCA_bus) {
179 /* The PS/2 uses level-triggered interrupts. You can't
180 turn them off, nor would you want to (any attempt to
181 enable edge-triggered interrupts usually gets intercepted by a
182 special hardware circuit). Hence we have to acknowledge
183 the timer interrupt. Through some incredibly stupid
184 design idea, the reset for IRQ 0 is done by setting the
185 high bit of the PPI port B (0x61). Note that some PS/2s,
186 notably the 55SX, work fine if this is removed. */
187
188 u8 irq_v = inb_p( 0x61 ); /* read the current state */
189 outb_p( irq_v|0x80, 0x61 ); /* reset the IRQ */
190 }
191
192 return IRQ_HANDLED;
193}
194
195/* not static: needed by APM */
196unsigned long read_persistent_clock(void)
197{
198 unsigned long retval;
199 unsigned long flags;
200
201 spin_lock_irqsave(&rtc_lock, flags);
202
203 retval = get_wallclock();
204
205 spin_unlock_irqrestore(&rtc_lock, flags);
206
207 return retval;
208}
209
210int update_persistent_clock(struct timespec now)
211{
212 return set_rtc_mmss(now.tv_sec);
213}
214
215extern void (*late_time_init)(void);
216/* Duplicate of time_init() below, with hpet_enable part added */
217void __init hpet_time_init(void)
218{
219 if (!hpet_enable())
220 setup_pit_timer();
221 time_init_hook();
222}
223
224/*
225 * This is called directly from init code; we must delay timer setup in the
226 * HPET case as we can't make the decision to turn on HPET this early in the
227 * boot process.
228 *
229 * The chosen time_init function will usually be hpet_time_init, above, but
230 * in the case of virtual hardware, an alternative function may be substituted.
231 */
232void __init time_init(void)
233{
234 tsc_init();
235 late_time_init = choose_time_init();
236}