kernel-ark/arch/i386/kernel/time.c
Venkatesh Pallipadi 6eb0a0fd05 [PATCH] i386: Handle missing local APIC timer interrupts on C3 state
Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we
disable local APIC timer and switch to using a broadcast from external timer
interrupt (IRQ 0). This is needed because Intel CPUs stop the local
APIC timer in C3.  This is currently only enabled for Intel CPUs.

Patch below adds the code for i386 and also the ACPI hunk.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-11 19:04:54 -08:00

492 lines
12 KiB
C

/*
* linux/arch/i386/kernel/time.c
*
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*
* This file contains the PC-specific time handling details:
* reading the RTC at bootup, etc..
* 1994-07-02 Alan Modra
* fixed set_rtc_mmss, fixed time.year for >= 2000, new mktime
* 1995-03-26 Markus Kuhn
* fixed 500 ms bug at call to set_rtc_mmss, fixed DS12887
* precision CMOS clock update
* 1996-05-03 Ingo Molnar
* fixed time warps in do_[slow|fast]_gettimeoffset()
* 1997-09-10 Updated NTP code according to technical memorandum Jan '96
* "A Kernel Model for Precision Timekeeping" by Dave Mills
* 1998-09-05 (Various)
* More robust do_fast_gettimeoffset() algorithm implemented
* (works with APM, Cyrix 6x86MX and Centaur C6),
* monotonic gettimeofday() with fast_get_timeoffset(),
* drift-proof precision TSC calibration on boot
* (C. Scott Ananian <cananian@alumni.princeton.edu>, Andrew D.
* Balsa <andrebalsa@altern.org>, Philip Gladstone <philip@raptor.com>;
* ported from 2.0.35 Jumbo-9 by Michael Krause <m.krause@tu-harburg.de>).
* 1998-12-16 Andrea Arcangeli
* Fixed Jumbo-9 code in 2.1.131: do_gettimeofday was missing 1 jiffy
* because was not accounting lost_ticks.
* 1998-12-24 Copyright (C) 1998 Andrea Arcangeli
* Fixed a xtime SMP race (we need the xtime_lock rw spinlock to
* serialize accesses to xtime/lost_ticks).
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/param.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/bcd.h>
#include <linux/efi.h>
#include <linux/mca.h>
#include <asm/io.h>
#include <asm/smp.h>
#include <asm/irq.h>
#include <asm/msr.h>
#include <asm/delay.h>
#include <asm/mpspec.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/timer.h>
#include "mach_time.h"
#include <linux/timex.h>
#include <linux/config.h>
#include <asm/hpet.h>
#include <asm/arch_hooks.h>
#include "io_ports.h"
#include <asm/i8259.h>
int pit_latch_buggy; /* extern */
#include "do_timer.h"
unsigned int cpu_khz; /* Detected as we calibrate the TSC */
EXPORT_SYMBOL(cpu_khz);
extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
#include <asm/i8253.h>
DEFINE_SPINLOCK(i8253_lock);
EXPORT_SYMBOL(i8253_lock);
struct timer_opts *cur_timer __read_mostly = &timer_none;
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
* CMOS/RTC registers. See include/asm-i386/mc146818rtc.h for details.
*/
volatile unsigned long cmos_lock = 0;
EXPORT_SYMBOL(cmos_lock);
/* Routines for accessing the CMOS RAM/RTC. */
unsigned char rtc_cmos_read(unsigned char addr)
{
unsigned char val;
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
val = inb_p(RTC_PORT(1));
lock_cmos_suffix(addr);
return val;
}
EXPORT_SYMBOL(rtc_cmos_read);
void rtc_cmos_write(unsigned char val, unsigned char addr)
{
lock_cmos_prefix(addr);
outb_p(addr, RTC_PORT(0));
outb_p(val, RTC_PORT(1));
lock_cmos_suffix(addr);
}
EXPORT_SYMBOL(rtc_cmos_write);
/*
* This version of gettimeofday has microsecond resolution
* and better than microsecond precision on fast x86 machines with TSC.
*/
void do_gettimeofday(struct timeval *tv)
{
unsigned long seq;
unsigned long usec, sec;
unsigned long max_ntp_tick;
do {
unsigned long lost;
seq = read_seqbegin(&xtime_lock);
usec = cur_timer->get_offset();
lost = jiffies - wall_jiffies;
/*
* If time_adjust is negative then NTP is slowing the clock
* so make sure not to go into next possible interval.
* Better to lose some accuracy than have time go backwards..
*/
if (unlikely(time_adjust < 0)) {
max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
usec = min(usec, max_ntp_tick);
if (lost)
usec += lost * max_ntp_tick;
}
else if (unlikely(lost))
usec += lost * (USEC_PER_SEC / HZ);
sec = xtime.tv_sec;
usec += (xtime.tv_nsec / 1000);
} while (read_seqretry(&xtime_lock, seq));
while (usec >= 1000000) {
usec -= 1000000;
sec++;
}
tv->tv_sec = sec;
tv->tv_usec = usec;
}
EXPORT_SYMBOL(do_gettimeofday);
int do_settimeofday(struct timespec *tv)
{
time_t wtm_sec, sec = tv->tv_sec;
long wtm_nsec, nsec = tv->tv_nsec;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
write_seqlock_irq(&xtime_lock);
/*
* This is revolting. We need to set "xtime" correctly. However, the
* value in this location is the value at the most recent update of
* wall time. Discover what correction gettimeofday() would have
* made, and then undo it!
*/
nsec -= cur_timer->get_offset() * NSEC_PER_USEC;
nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
set_normalized_timespec(&xtime, sec, nsec);
set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
ntp_clear();
write_sequnlock_irq(&xtime_lock);
clock_was_set();
return 0;
}
EXPORT_SYMBOL(do_settimeofday);
static int set_rtc_mmss(unsigned long nowtime)
{
int retval;
WARN_ON(irqs_disabled());
/* gets recalled with irq locally disabled */
spin_lock_irq(&rtc_lock);
if (efi_enabled)
retval = efi_set_rtc_mmss(nowtime);
else
retval = mach_set_rtc_mmss(nowtime);
spin_unlock_irq(&rtc_lock);
return retval;
}
int timer_ack;
/* monotonic_clock(): returns # of nanoseconds passed since time_init()
* Note: This function is required to return accurate
* time even in the absence of multiple timer ticks.
*/
unsigned long long monotonic_clock(void)
{
return cur_timer->monotonic_clock();
}
EXPORT_SYMBOL(monotonic_clock);
#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
unsigned long profile_pc(struct pt_regs *regs)
{
unsigned long pc = instruction_pointer(regs);
if (in_lock_functions(pc))
return *(unsigned long *)(regs->ebp + 4);
return pc;
}
EXPORT_SYMBOL(profile_pc);
#endif
/*
* timer_interrupt() needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick
*/
static inline void do_timer_interrupt(int irq, struct pt_regs *regs)
{
#ifdef CONFIG_X86_IO_APIC
if (timer_ack) {
/*
* Subtle, when I/O APICs are used we have to ack timer IRQ
* manually to reset the IRR bit for do_slow_gettimeoffset().
* This will also deassert NMI lines for the watchdog if run
* on an 82489DX-based system.
*/
spin_lock(&i8259A_lock);
outb(0x0c, PIC_MASTER_OCW3);
/* Ack the IRQ; AEOI will end it automatically. */
inb(PIC_MASTER_POLL);
spin_unlock(&i8259A_lock);
}
#endif
do_timer_interrupt_hook(regs);
if (MCA_bus) {
/* The PS/2 uses level-triggered interrupts. You can't
turn them off, nor would you want to (any attempt to
enable edge-triggered interrupts usually gets intercepted by a
special hardware circuit). Hence we have to acknowledge
the timer interrupt. Through some incredibly stupid
design idea, the reset for IRQ 0 is done by setting the
high bit of the PPI port B (0x61). Note that some PS/2s,
notably the 55SX, work fine if this is removed. */
irq = inb_p( 0x61 ); /* read the current state */
outb_p( irq|0x80, 0x61 ); /* reset the IRQ */
}
}
/*
* This is the same as the above, except we _also_ save the current
* Time Stamp Counter value at the time of the timer interrupt, so that
* we later on can estimate the time of day more exactly.
*/
irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
/*
* Here we are in the timer irq handler. We just have irqs locally
* disabled but we don't know if the timer_bh is running on the other
* CPU. We need to avoid to SMP race with it. NOTE: we don' t need
* the irq version of write_lock because as just said we have irq
* locally disabled. -arca
*/
write_seqlock(&xtime_lock);
cur_timer->mark_offset();
do_timer_interrupt(irq, regs);
write_sequnlock(&xtime_lock);
#ifdef CONFIG_X86_LOCAL_APIC
if (using_apic_timer)
smp_send_timer_broadcast_ipi(regs);
#endif
return IRQ_HANDLED;
}
/* not static: needed by APM */
unsigned long get_cmos_time(void)
{
unsigned long retval;
spin_lock(&rtc_lock);
if (efi_enabled)
retval = efi_get_time();
else
retval = mach_get_cmos_time();
spin_unlock(&rtc_lock);
return retval;
}
EXPORT_SYMBOL(get_cmos_time);
static void sync_cmos_clock(unsigned long dummy);
static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0);
static void sync_cmos_clock(unsigned long dummy)
{
struct timeval now, next;
int fail = 1;
/*
* If we have an externally synchronized Linux clock, then update
* CMOS clock accordingly every ~11 minutes. Set_rtc_mmss() has to be
* called as close as possible to 500 ms before the new second starts.
* This code is run on a timer. If the clock is set, that timer
* may not expire at the correct time. Thus, we adjust...
*/
if (!ntp_synced())
/*
* Not synced, exit, do not restart a timer (if one is
* running, let it run out).
*/
return;
do_gettimeofday(&now);
if (now.tv_usec >= USEC_AFTER - ((unsigned) TICK_SIZE) / 2 &&
now.tv_usec <= USEC_BEFORE + ((unsigned) TICK_SIZE) / 2)
fail = set_rtc_mmss(now.tv_sec);
next.tv_usec = USEC_AFTER - now.tv_usec;
if (next.tv_usec <= 0)
next.tv_usec += USEC_PER_SEC;
if (!fail)
next.tv_sec = 659;
else
next.tv_sec = 0;
if (next.tv_usec >= USEC_PER_SEC) {
next.tv_sec++;
next.tv_usec -= USEC_PER_SEC;
}
mod_timer(&sync_cmos_timer, jiffies + timeval_to_jiffies(&next));
}
void notify_arch_cmos_timer(void)
{
mod_timer(&sync_cmos_timer, jiffies + 1);
}
static long clock_cmos_diff, sleep_start;
static struct timer_opts *last_timer;
static int timer_suspend(struct sys_device *dev, pm_message_t state)
{
/*
* Estimate time zone so that set_time can update the clock
*/
clock_cmos_diff = -get_cmos_time();
clock_cmos_diff += get_seconds();
sleep_start = get_cmos_time();
last_timer = cur_timer;
cur_timer = &timer_none;
if (last_timer->suspend)
last_timer->suspend(state);
return 0;
}
static int timer_resume(struct sys_device *dev)
{
unsigned long flags;
unsigned long sec;
unsigned long sleep_length;
#ifdef CONFIG_HPET_TIMER
if (is_hpet_enabled())
hpet_reenable();
#endif
setup_pit_timer();
sec = get_cmos_time() + clock_cmos_diff;
sleep_length = (get_cmos_time() - sleep_start) * HZ;
write_seqlock_irqsave(&xtime_lock, flags);
xtime.tv_sec = sec;
xtime.tv_nsec = 0;
write_sequnlock_irqrestore(&xtime_lock, flags);
jiffies += sleep_length;
wall_jiffies += sleep_length;
if (last_timer->resume)
last_timer->resume();
cur_timer = last_timer;
last_timer = NULL;
touch_softlockup_watchdog();
return 0;
}
static struct sysdev_class timer_sysclass = {
.resume = timer_resume,
.suspend = timer_suspend,
set_kset_name("timer"),
};
/* XXX this driverfs stuff should probably go elsewhere later -john */
static struct sys_device device_timer = {
.id = 0,
.cls = &timer_sysclass,
};
static int time_init_device(void)
{
int error = sysdev_class_register(&timer_sysclass);
if (!error)
error = sysdev_register(&device_timer);
return error;
}
device_initcall(time_init_device);
#ifdef CONFIG_HPET_TIMER
extern void (*late_time_init)(void);
/* Duplicate of time_init() below, with hpet_enable part added */
static void __init hpet_time_init(void)
{
xtime.tv_sec = get_cmos_time();
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
if ((hpet_enable() >= 0) && hpet_use_timer) {
printk("Using HPET for base-timer\n");
}
cur_timer = select_timer();
printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
time_init_hook();
}
#endif
void __init time_init(void)
{
#ifdef CONFIG_HPET_TIMER
if (is_hpet_capable()) {
/*
* HPET initialization needs to do memory-mapped io. So, let
* us do a late initialization after mem_init().
*/
late_time_init = hpet_time_init;
return;
}
#endif
xtime.tv_sec = get_cmos_time();
xtime.tv_nsec = (INITIAL_JIFFIES % HZ) * (NSEC_PER_SEC / HZ);
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
cur_timer = select_timer();
printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
time_init_hook();
}