blob: 368b1942b39aba509cfafe7fae629ef400a7a243 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * "High Precision Event Timer" based timekeeping.
3 *
4 * Copyright (c) 1991,1992,1995 Linus Torvalds
5 * Copyright (c) 1994 Alan Modra
6 * Copyright (c) 1995 Markus Kuhn
7 * Copyright (c) 1996 Ingo Molnar
8 * Copyright (c) 1998 Andrea Arcangeli
Vojtech Pavlik2f82bde2006-06-26 13:58:38 +02009 * Copyright (c) 2002,2006 Vojtech Pavlik
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * Copyright (c) 2003 Andi Kleen
11 * RTC support code taken from arch/i386/kernel/timers/time_hpet.c
12 */
13
14#include <linux/kernel.h>
15#include <linux/sched.h>
16#include <linux/interrupt.h>
17#include <linux/init.h>
18#include <linux/mc146818rtc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/time.h>
20#include <linux/ioport.h>
21#include <linux/module.h>
22#include <linux/device.h>
23#include <linux/sysdev.h>
24#include <linux/bcd.h>
Vojtech Pavlika670fad2006-09-26 10:52:28 +020025#include <linux/notifier.h>
26#include <linux/cpu.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/kallsyms.h>
Andi Kleen312df5f2005-05-16 21:53:28 -070028#include <linux/acpi.h>
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +020029#include <linux/clockchips.h>
30
Andi Kleen8d916402005-05-31 14:39:26 -070031#ifdef CONFIG_ACPI
Andi Kleen312df5f2005-05-16 21:53:28 -070032#include <acpi/achware.h> /* for PM timer frequency */
Andi Kleen0e5f61b2006-07-29 21:42:37 +020033#include <acpi/acpi_bus.h>
Andi Kleen8d916402005-05-31 14:39:26 -070034#endif
Thomas Gleixner28318da2007-07-21 17:11:18 +020035#include <asm/i8253.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <asm/pgtable.h>
37#include <asm/vsyscall.h>
38#include <asm/timex.h>
39#include <asm/proto.h>
40#include <asm/hpet.h>
41#include <asm/sections.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/hpet.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <asm/apic.h>
john stultzc37e7bb2007-02-16 01:28:19 -080044#include <asm/hpet.h>
Andi Kleen803d80f2007-05-02 19:27:05 +020045#include <asm/mpspec.h>
Joerg Roedel6b37f5a2007-05-02 19:27:06 +020046#include <asm/nmi.h>
Andi Kleen2aae9502007-07-21 17:10:01 +020047#include <asm/vgtod.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070048
49DEFINE_SPINLOCK(rtc_lock);
Andi Kleen2ee60e172006-06-26 13:59:44 +020050EXPORT_SYMBOL(rtc_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
Linus Torvalds1da177e2005-04-16 15:20:36 -070052volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
Linus Torvalds1da177e2005-04-16 15:20:36 -070054unsigned long profile_pc(struct pt_regs *regs)
55{
56 unsigned long pc = instruction_pointer(regs);
57
Andi Kleen31679f32006-09-26 10:52:28 +020058 /* Assume the lock function has either no stack frame or a copy
59 of eflags from PUSHF
60 Eflags always has bits 22 and up cleared unlike kernel addresses. */
Andi Kleend5a26012006-07-28 14:44:42 +020061 if (!user_mode(regs) && in_lock_functions(pc)) {
Andi Kleen31679f32006-09-26 10:52:28 +020062 unsigned long *sp = (unsigned long *)regs->rsp;
63 if (sp[0] >> 22)
64 return sp[0];
65 if (sp[1] >> 22)
66 return sp[1];
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 }
68 return pc;
69}
70EXPORT_SYMBOL(profile_pc);
71
72/*
73 * In order to set the CMOS clock precisely, set_rtc_mmss has to be called 500
74 * ms after the second nowtime has started, because when nowtime is written
75 * into the registers of the CMOS clock, it will jump to the next second
76 * precisely 500 ms later. Check the Motorola MC146818A or Dallas DS12887 data
77 * sheet for details.
78 */
79
Thomas Gleixneraf745222007-07-21 17:10:11 +020080static int set_rtc_mmss(unsigned long nowtime)
Linus Torvalds1da177e2005-04-16 15:20:36 -070081{
Thomas Gleixneraf745222007-07-21 17:10:11 +020082 int retval = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070083 int real_seconds, real_minutes, cmos_minutes;
84 unsigned char control, freq_select;
David P. Reedc399da02007-11-14 17:47:35 -050085 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -070086
87/*
David P. Reedc399da02007-11-14 17:47:35 -050088 * set_rtc_mmss is called when irqs are enabled, so disable irqs here
Linus Torvalds1da177e2005-04-16 15:20:36 -070089 */
David P. Reedc399da02007-11-14 17:47:35 -050090 spin_lock_irqsave(&rtc_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -070091/*
92 * Tell the clock it's being set and stop it.
93 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 control = CMOS_READ(RTC_CONTROL);
95 CMOS_WRITE(control | RTC_SET, RTC_CONTROL);
96
97 freq_select = CMOS_READ(RTC_FREQ_SELECT);
98 CMOS_WRITE(freq_select | RTC_DIV_RESET2, RTC_FREQ_SELECT);
99
100 cmos_minutes = CMOS_READ(RTC_MINUTES);
101 BCD_TO_BIN(cmos_minutes);
102
103/*
104 * since we're only adjusting minutes and seconds, don't interfere with hour
105 * overflow. This avoids messing with unknown time zones but requires your RTC
106 * not to be off by more than 15 minutes. Since we're calling it only when
107 * our clock is externally synchronized using NTP, this shouldn't be a problem.
108 */
109
110 real_seconds = nowtime % 60;
111 real_minutes = nowtime / 60;
112 if (((abs(real_minutes - cmos_minutes) + 15) / 30) & 1)
113 real_minutes += 30; /* correct for half hour time zone */
114 real_minutes %= 60;
115
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 if (abs(real_minutes - cmos_minutes) >= 30) {
117 printk(KERN_WARNING "time.c: can't update CMOS clock "
118 "from %d to %d\n", cmos_minutes, real_minutes);
Thomas Gleixneraf745222007-07-21 17:10:11 +0200119 retval = -1;
Andi Kleen28456ed2006-03-25 16:30:37 +0100120 } else {
Andi Kleen0b913172006-01-11 22:45:33 +0100121 BIN_TO_BCD(real_seconds);
122 BIN_TO_BCD(real_minutes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123 CMOS_WRITE(real_seconds, RTC_SECONDS);
124 CMOS_WRITE(real_minutes, RTC_MINUTES);
125 }
126
127/*
128 * The following flags have to be released exactly in this order, otherwise the
129 * DS12887 (popular MC146818A clone with integrated battery and quartz) will
130 * not reset the oscillator and will not update precisely 500 ms later. You
131 * won't find this mentioned in the Dallas Semiconductor data sheets, but who
132 * believes data sheets anyway ... -- Markus Kuhn
133 */
134
135 CMOS_WRITE(control, RTC_CONTROL);
136 CMOS_WRITE(freq_select, RTC_FREQ_SELECT);
137
David P. Reedc399da02007-11-14 17:47:35 -0500138 spin_unlock_irqrestore(&rtc_lock, flags);
Thomas Gleixneraf745222007-07-21 17:10:11 +0200139
140 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
Thomas Gleixneraf745222007-07-21 17:10:11 +0200143int update_persistent_clock(struct timespec now)
144{
145 return set_rtc_mmss(now.tv_sec);
146}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +0200148static irqreturn_t timer_event_interrupt(int irq, void *dev_id)
149{
Thomas Gleixner4e77ae32007-10-12 23:04:07 +0200150 add_pda(irq0_irqs, 1);
151
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +0200152 global_clock_event->event_handler(global_clock_event);
153
154 return IRQ_HANDLED;
155}
156
Thomas Gleixneref81ab22007-07-21 17:10:12 +0200157unsigned long read_persistent_clock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158{
Matt Mackall641f71f2006-03-28 01:56:01 -0800159 unsigned int year, mon, day, hour, min, sec;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 unsigned long flags;
Alexey Starikovskiyad718602007-02-02 19:48:19 +0300161 unsigned century = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163 spin_lock_irqsave(&rtc_lock, flags);
David P. Reedbbbd9992007-11-14 20:14:50 -0500164 /*
165 * if UIP is clear, then we have >= 244 microseconds before RTC
166 * registers will be updated. Spec sheet says that this is the
167 * reliable way to read RTC - registers invalid (off bus) during update
168 */
169 while ((CMOS_READ(RTC_FREQ_SELECT) & RTC_UIP))
170 cpu_relax();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
David P. Reedbbbd9992007-11-14 20:14:50 -0500172
173 /* now read all RTC registers while stable with interrupts disabled */
174 sec = CMOS_READ(RTC_SECONDS);
175 min = CMOS_READ(RTC_MINUTES);
176 hour = CMOS_READ(RTC_HOURS);
177 day = CMOS_READ(RTC_DAY_OF_MONTH);
178 mon = CMOS_READ(RTC_MONTH);
179 year = CMOS_READ(RTC_YEAR);
Andi Kleen6954bee2006-03-25 16:30:31 +0100180#ifdef CONFIG_ACPI
David P. Reedbbbd9992007-11-14 20:14:50 -0500181 if (acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID &&
182 acpi_gbl_FADT.century)
183 century = CMOS_READ(acpi_gbl_FADT.century);
Andi Kleen6954bee2006-03-25 16:30:31 +0100184#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 spin_unlock_irqrestore(&rtc_lock, flags);
186
Andi Kleen0b913172006-01-11 22:45:33 +0100187 /*
188 * We know that x86-64 always uses BCD format, no need to check the
189 * config register.
Thomas Gleixner2618f862007-07-21 17:10:18 +0200190 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191
Andi Kleen0b913172006-01-11 22:45:33 +0100192 BCD_TO_BIN(sec);
193 BCD_TO_BIN(min);
194 BCD_TO_BIN(hour);
195 BCD_TO_BIN(day);
196 BCD_TO_BIN(mon);
197 BCD_TO_BIN(year);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
Alexey Starikovskiyad718602007-02-02 19:48:19 +0300199 if (century) {
200 BCD_TO_BIN(century);
201 year += century * 100;
202 printk(KERN_INFO "Extended CMOS year: %d\n", century * 100);
Thomas Gleixner2618f862007-07-21 17:10:18 +0200203 } else {
Andi Kleen6954bee2006-03-25 16:30:31 +0100204 /*
205 * x86-64 systems only exists since 2002.
206 * This will work up to Dec 31, 2100
Thomas Gleixner2618f862007-07-21 17:10:18 +0200207 */
Andi Kleen6954bee2006-03-25 16:30:31 +0100208 year += 2000;
209 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211 return mktime(year, mon, day, hour, min, sec);
212}
213
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200214/* calibrate_cpu is used on systems with fixed rate TSCs to determine
215 * processor frequency */
216#define TICK_COUNT 100000000
217static unsigned int __init tsc_calibrate_cpu_khz(void)
218{
Thomas Gleixner2618f862007-07-21 17:10:18 +0200219 int tsc_start, tsc_now;
220 int i, no_ctr_free;
221 unsigned long evntsel3 = 0, pmc3 = 0, pmc_now = 0;
222 unsigned long flags;
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200223
Thomas Gleixner2618f862007-07-21 17:10:18 +0200224 for (i = 0; i < 4; i++)
225 if (avail_to_resrv_perfctr_nmi_bit(i))
226 break;
227 no_ctr_free = (i == 4);
228 if (no_ctr_free) {
229 i = 3;
230 rdmsrl(MSR_K7_EVNTSEL3, evntsel3);
231 wrmsrl(MSR_K7_EVNTSEL3, 0);
232 rdmsrl(MSR_K7_PERFCTR3, pmc3);
233 } else {
234 reserve_perfctr_nmi(MSR_K7_PERFCTR0 + i);
235 reserve_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
236 }
237 local_irq_save(flags);
238 /* start meauring cycles, incrementing from 0 */
239 wrmsrl(MSR_K7_PERFCTR0 + i, 0);
240 wrmsrl(MSR_K7_EVNTSEL0 + i, 1 << 22 | 3 << 16 | 0x76);
241 rdtscl(tsc_start);
242 do {
243 rdmsrl(MSR_K7_PERFCTR0 + i, pmc_now);
244 tsc_now = get_cycles_sync();
245 } while ((tsc_now - tsc_start) < TICK_COUNT);
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200246
Thomas Gleixner2618f862007-07-21 17:10:18 +0200247 local_irq_restore(flags);
248 if (no_ctr_free) {
249 wrmsrl(MSR_K7_EVNTSEL3, 0);
250 wrmsrl(MSR_K7_PERFCTR3, pmc3);
251 wrmsrl(MSR_K7_EVNTSEL3, evntsel3);
252 } else {
253 release_perfctr_nmi(MSR_K7_PERFCTR0 + i);
254 release_evntsel_nmi(MSR_K7_EVNTSEL0 + i);
255 }
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200256
Thomas Gleixner2618f862007-07-21 17:10:18 +0200257 return pmc_now * tsc_khz / (tsc_now - tsc_start);
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200258}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260static struct irqaction irq0 = {
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +0200261 .handler = timer_event_interrupt,
Venki Pallipadi5fa3a242007-10-12 23:04:06 +0200262 .flags = IRQF_DISABLED | IRQF_IRQPOLL | IRQF_NOBALANCING,
Bernhard Wallee6d828f2007-05-08 00:35:28 -0700263 .mask = CPU_MASK_NONE,
Thomas Gleixner2618f862007-07-21 17:10:18 +0200264 .name = "timer"
Linus Torvalds1da177e2005-04-16 15:20:36 -0700265};
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267void __init time_init(void)
268{
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +0200269 if (!hpet_enable())
270 setup_pit_timer();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
Thomas Gleixnerb8ce3352007-10-12 23:04:07 +0200272 setup_irq(0, &irq0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273
Thomas Gleixnerd3716982007-10-12 23:04:06 +0200274 tsc_calibrate();
275
Joerg Roedel6b37f5a2007-05-02 19:27:06 +0200276 cpu_khz = tsc_khz;
277 if (cpu_has(&boot_cpu_data, X86_FEATURE_CONSTANT_TSC) &&
278 boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
279 boot_cpu_data.x86 == 16)
280 cpu_khz = tsc_calibrate_cpu_khz();
281
Andi Kleen312df5f2005-05-16 21:53:28 -0700282 if (unsynchronized_tsc())
john stultz5a90cf22007-05-02 19:27:08 +0200283 mark_tsc_unstable("TSCs unsynchronized");
Vojtech Pavlika670fad2006-09-26 10:52:28 +0200284
john stultz2d0c87c2007-02-16 01:28:18 -0800285 if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
Vojtech Pavlikc08c8202006-09-26 10:52:28 +0200286 vgetcpu_mode = VGETCPU_RDTSCP;
287 else
288 vgetcpu_mode = VGETCPU_LSL;
289
Vojtech Pavlika670fad2006-09-26 10:52:28 +0200290 printk(KERN_INFO "time.c: Detected %d.%03d MHz processor.\n",
291 cpu_khz / 1000, cpu_khz % 1000);
john stultz6bb74df2007-03-05 00:30:50 -0800292 init_tsc_clocksource();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293}