1 // SPDX-License-Identifier: GPL-2.0 <<
2 /* 1 /*
3 * arch/sh/kernel/time.c !! 2 * linux/arch/i386/kernel/time.c
4 * 3 *
5 * Copyright (C) 1999 Tetsuya Okada & Niibe !! 4 * Copyright (C) 1991, 1992, 1995 Linus Torvalds
6 * Copyright (C) 2000 Philipp Rumpf <prumpf@ !! 5 *
7 * Copyright (C) 2002 - 2009 Paul Mundt !! 6 * This file contains the PC-specific time handling details:
8 * Copyright (C) 2002 M. R. Brown <mrbrown@ !! 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).
9 */ 31 */
>> 32
>> 33 #include <linux/errno.h>
>> 34 #include <linux/sched.h>
10 #include <linux/kernel.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>
11 #include <linux/init.h> 42 #include <linux/init.h>
12 #include <linux/profile.h> <<
13 #include <linux/timex.h> <<
14 #include <linux/sched.h> <<
15 #include <linux/clockchips.h> <<
16 #include <linux/platform_device.h> <<
17 #include <linux/smp.h> 43 #include <linux/smp.h>
18 #include <linux/rtc.h> !! 44 #include <linux/module.h>
19 #include <asm/clock.h> !! 45 #include <linux/sysdev.h>
20 #include <asm/rtc.h> !! 46 #include <linux/bcd.h>
21 #include <asm/platform_early.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>
>> 57
>> 58 #include "mach_time.h"
>> 59
>> 60 #include <linux/timex.h>
>> 61 #include <linux/config.h>
>> 62
>> 63 #include <asm/hpet.h>
>> 64
>> 65 #include <asm/arch_hooks.h>
>> 66
>> 67 #include "io_ports.h"
>> 68
>> 69 extern spinlock_t i8259A_lock;
>> 70 int pit_latch_buggy; /* extern */
>> 71
>> 72 #include "do_timer.h"
>> 73
>> 74 u64 jiffies_64 = INITIAL_JIFFIES;
>> 75
>> 76 EXPORT_SYMBOL(jiffies_64);
>> 77
>> 78 unsigned long cpu_khz; /* Detected as we calibrate the TSC */
>> 79
>> 80 extern unsigned long wall_jiffies;
>> 81
>> 82 spinlock_t rtc_lock = SPIN_LOCK_UNLOCKED;
>> 83
>> 84 spinlock_t i8253_lock = SPIN_LOCK_UNLOCKED;
>> 85 EXPORT_SYMBOL(i8253_lock);
>> 86
>> 87 struct timer_opts *cur_timer = &timer_none;
>> 88
>> 89 /*
>> 90 * This version of gettimeofday has microsecond resolution
>> 91 * and better than microsecond precision on fast x86 machines with TSC.
>> 92 */
>> 93 void do_gettimeofday(struct timeval *tv)
>> 94 {
>> 95 unsigned long seq;
>> 96 unsigned long usec, sec;
>> 97 unsigned long max_ntp_tick = tick_usec - tickadj;
>> 98
>> 99 do {
>> 100 unsigned long lost;
>> 101
>> 102 seq = read_seqbegin(&xtime_lock);
>> 103
>> 104 usec = cur_timer->get_offset();
>> 105 lost = jiffies - wall_jiffies;
>> 106
>> 107 /*
>> 108 * If time_adjust is negative then NTP is slowing the clock
>> 109 * so make sure not to go into next possible interval.
>> 110 * Better to lose some accuracy than have time go backwards..
>> 111 */
>> 112 if (unlikely(time_adjust < 0)) {
>> 113 usec = min(usec, max_ntp_tick);
>> 114
>> 115 if (lost)
>> 116 usec += lost * max_ntp_tick;
>> 117 }
>> 118 else if (unlikely(lost))
>> 119 usec += lost * tick_usec;
>> 120
>> 121 sec = xtime.tv_sec;
>> 122 usec += (xtime.tv_nsec / 1000);
>> 123 } while (read_seqretry(&xtime_lock, seq));
>> 124
>> 125 while (usec >= 1000000) {
>> 126 usec -= 1000000;
>> 127 sec++;
>> 128 }
>> 129
>> 130 tv->tv_sec = sec;
>> 131 tv->tv_usec = usec;
>> 132 }
>> 133
>> 134 EXPORT_SYMBOL(do_gettimeofday);
22 135
23 static void __init sh_late_time_init(void) !! 136 int do_settimeofday(struct timespec *tv)
24 { 137 {
>> 138 time_t wtm_sec, sec = tv->tv_sec;
>> 139 long wtm_nsec, nsec = tv->tv_nsec;
>> 140
>> 141 if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
>> 142 return -EINVAL;
>> 143
>> 144 write_seqlock_irq(&xtime_lock);
25 /* 145 /*
26 * Make sure all compiled-in early tim !! 146 * This is revolting. We need to set "xtime" correctly. However, the
27 * !! 147 * value in this location is the value at the most recent update of
28 * Run probe() for two "earlytimer" de !! 148 * wall time. Discover what correction gettimeofday() would have
29 * clockevents and clocksource devices !! 149 * made, and then undo it!
30 * that only a clockevents device is a <<
31 * clocksource and the jiffies clockso <<
32 * instead. No error handling is neces <<
33 */ 150 */
34 sh_early_platform_driver_register_all( !! 151 nsec -= cur_timer->get_offset() * NSEC_PER_USEC;
35 sh_early_platform_driver_probe("earlyt !! 152 nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
>> 153
>> 154 wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
>> 155 wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
>> 156
>> 157 set_normalized_timespec(&xtime, sec, nsec);
>> 158 set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
>> 159
>> 160 time_adjust = 0; /* stop active adjtime() */
>> 161 time_status |= STA_UNSYNC;
>> 162 time_maxerror = NTP_PHASE_LIMIT;
>> 163 time_esterror = NTP_PHASE_LIMIT;
>> 164 write_sequnlock_irq(&xtime_lock);
>> 165 clock_was_set();
>> 166 return 0;
>> 167 }
>> 168
>> 169 EXPORT_SYMBOL(do_settimeofday);
>> 170
>> 171 static int set_rtc_mmss(unsigned long nowtime)
>> 172 {
>> 173 int retval;
>> 174
>> 175 /* gets recalled with irq locally disabled */
>> 176 spin_lock(&rtc_lock);
>> 177 retval = mach_set_rtc_mmss(nowtime);
>> 178 spin_unlock(&rtc_lock);
>> 179
>> 180 return retval;
>> 181 }
>> 182
>> 183 /* last time the cmos clock got updated */
>> 184 static long last_rtc_update;
>> 185
>> 186 int timer_ack;
>> 187
>> 188 /* monotonic_clock(): returns # of nanoseconds passed since time_init()
>> 189 * Note: This function is required to return accurate
>> 190 * time even in the absence of multiple timer ticks.
>> 191 */
>> 192 unsigned long long monotonic_clock(void)
>> 193 {
>> 194 return cur_timer->monotonic_clock();
>> 195 }
>> 196 EXPORT_SYMBOL(monotonic_clock);
>> 197
>> 198
>> 199 /*
>> 200 * timer_interrupt() needs to keep up the real-time clock,
>> 201 * as well as call the "do_timer()" routine every clocktick
>> 202 */
>> 203 static inline void do_timer_interrupt(int irq, void *dev_id,
>> 204 struct pt_regs *regs)
>> 205 {
>> 206 #ifdef CONFIG_X86_IO_APIC
>> 207 if (timer_ack) {
>> 208 /*
>> 209 * Subtle, when I/O APICs are used we have to ack timer IRQ
>> 210 * manually to reset the IRR bit for do_slow_gettimeoffset().
>> 211 * This will also deassert NMI lines for the watchdog if run
>> 212 * on an 82489DX-based system.
>> 213 */
>> 214 spin_lock(&i8259A_lock);
>> 215 outb(0x0c, PIC_MASTER_OCW3);
>> 216 /* Ack the IRQ; AEOI will end it automatically. */
>> 217 inb(PIC_MASTER_POLL);
>> 218 spin_unlock(&i8259A_lock);
>> 219 }
>> 220 #endif
>> 221
>> 222 do_timer_interrupt_hook(regs);
>> 223
>> 224 /*
>> 225 * If we have an externally synchronized Linux clock, then update
>> 226 * CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
>> 227 * called as close as possible to 500 ms before the new second starts.
>> 228 */
>> 229 if ((time_status & STA_UNSYNC) == 0 &&
>> 230 xtime.tv_sec > last_rtc_update + 660 &&
>> 231 (xtime.tv_nsec / 1000)
>> 232 >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 &&
>> 233 (xtime.tv_nsec / 1000)
>> 234 <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2) {
>> 235 if (set_rtc_mmss(xtime.tv_sec) == 0)
>> 236 last_rtc_update = xtime.tv_sec;
>> 237 else
>> 238 last_rtc_update = xtime.tv_sec - 600; /* do it again in 60 s */
>> 239 }
>> 240
>> 241 #ifdef CONFIG_MCA
>> 242 if( MCA_bus ) {
>> 243 /* The PS/2 uses level-triggered interrupts. You can't
>> 244 turn them off, nor would you want to (any attempt to
>> 245 enable edge-triggered interrupts usually gets intercepted by a
>> 246 special hardware circuit). Hence we have to acknowledge
>> 247 the timer interrupt. Through some incredibly stupid
>> 248 design idea, the reset for IRQ 0 is done by setting the
>> 249 high bit of the PPI port B (0x61). Note that some PS/2s,
>> 250 notably the 55SX, work fine if this is removed. */
>> 251
>> 252 irq = inb_p( 0x61 ); /* read the current state */
>> 253 outb_p( irq|0x80, 0x61 ); /* reset the IRQ */
>> 254 }
>> 255 #endif
>> 256 }
>> 257
>> 258 /*
>> 259 * This is the same as the above, except we _also_ save the current
>> 260 * Time Stamp Counter value at the time of the timer interrupt, so that
>> 261 * we later on can estimate the time of day more exactly.
>> 262 */
>> 263 irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
>> 264 {
>> 265 /*
>> 266 * Here we are in the timer irq handler. We just have irqs locally
>> 267 * disabled but we don't know if the timer_bh is running on the other
>> 268 * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
>> 269 * the irq version of write_lock because as just said we have irq
>> 270 * locally disabled. -arca
>> 271 */
>> 272 write_seqlock(&xtime_lock);
>> 273
>> 274 cur_timer->mark_offset();
>> 275
>> 276 do_timer_interrupt(irq, NULL, regs);
>> 277
>> 278 write_sequnlock(&xtime_lock);
>> 279 return IRQ_HANDLED;
>> 280 }
>> 281
>> 282 /* not static: needed by APM */
>> 283 unsigned long get_cmos_time(void)
>> 284 {
>> 285 unsigned long retval;
>> 286
>> 287 spin_lock(&rtc_lock);
>> 288
>> 289 retval = mach_get_cmos_time();
>> 290
>> 291 spin_unlock(&rtc_lock);
>> 292
>> 293 return retval;
>> 294 }
>> 295
>> 296 static struct sysdev_class pit_sysclass = {
>> 297 set_kset_name("pit"),
>> 298 };
>> 299
>> 300 /* XXX this driverfs stuff should probably go elsewhere later -john */
>> 301 static struct sys_device device_i8253 = {
>> 302 .id = 0,
>> 303 .cls = &pit_sysclass,
>> 304 };
>> 305
>> 306 static int time_init_device(void)
>> 307 {
>> 308 int error = sysdev_class_register(&pit_sysclass);
>> 309 if (!error)
>> 310 error = sys_device_register(&device_i8253);
>> 311 return error;
>> 312 }
>> 313
>> 314 device_initcall(time_init_device);
>> 315
>> 316 #ifdef CONFIG_HPET_TIMER
>> 317 extern void (*late_time_init)(void);
>> 318 /* Duplicate of time_init() below, with hpet_enable part added */
>> 319 void __init hpet_time_init(void)
>> 320 {
>> 321 xtime.tv_sec = get_cmos_time();
>> 322 wall_to_monotonic.tv_sec = -xtime.tv_sec;
>> 323 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
>> 324 wall_to_monotonic.tv_nsec = -xtime.tv_nsec;
>> 325
>> 326 if (hpet_enable() >= 0) {
>> 327 printk("Using HPET for base-timer\n");
>> 328 }
>> 329
>> 330 cur_timer = select_timer();
>> 331 time_init_hook();
36 } 332 }
>> 333 #endif
37 334
38 void __init time_init(void) 335 void __init time_init(void)
39 { 336 {
40 timer_probe(); !! 337 #ifdef CONFIG_HPET_TIMER
>> 338 if (is_hpet_capable()) {
>> 339 /*
>> 340 * HPET initialization needs to do memory-mapped io. So, let
>> 341 * us do a late initialization after mem_init().
>> 342 */
>> 343 late_time_init = hpet_time_init;
>> 344 return;
>> 345 }
>> 346 #endif
41 347
42 clk_init(); !! 348 xtime.tv_sec = get_cmos_time();
>> 349 wall_to_monotonic.tv_sec = -xtime.tv_sec;
>> 350 xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
>> 351 wall_to_monotonic.tv_nsec = -xtime.tv_nsec;
43 352
44 late_time_init = sh_late_time_init; !! 353 cur_timer = select_timer();
>> 354 time_init_hook();
45 } 355 }
46 356
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