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[PATCH] time: x86_64: split x86_64/kernel/time.c up

Browse source 
In preparation for the x86_64 generic time conversion, this patch splits out
TSC and HPET related code from arch/x86_64/kernel/time.c into respective
hpet.c and tsc.c files.

[akpm@osdl.org: fix printk timestamps]
[akpm@osdl.org: cleanup]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
john stultz 2007-02-16 01:28:19 -08:00 committed by Linus Torvalds
parent 2d0c87c3bc
commit c37e7bb5d2
7 changed files with 687 additions and 663 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/x86_64/kernel/Makefile
View file

@ -8,7 +8,7 @@ obj-y := process.o signal.o entry.o traps.o irq.o \
ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_x86_64.o \
x8664_ksyms.o i387.o syscall.o vsyscall.o \
setup64.o bootflag.o e820.o reboot.o quirks.o i8237.o \
pci-dma.o pci-nommu.o alternative.o
pci-dma.o pci-nommu.o alternative.o hpet.o tsc.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-$(CONFIG_X86_MCE) += mce.o therm_throt.o

453
arch/x86_64/kernel/hpet.c Normal file
View file

@ -0,0 +1,453 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/mc146818rtc.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/ioport.h>
#include <linux/acpi.h>
#include <linux/hpet.h>
#include <asm/pgtable.h>
#include <asm/vsyscall.h>
#include <asm/timex.h>
#include <asm/hpet.h>
int nohpet __initdata;
unsigned long hpet_address;
unsigned long hpet_period; /* fsecs / HPET clock */
unsigned long hpet_tick; /* HPET clocks / interrupt */
int hpet_use_timer; /* Use counter of hpet for time keeping,
* otherwise PIT
*/
unsigned int do_gettimeoffset_hpet(void)
{
/* cap counter read to one tick to avoid inconsistencies */
unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last;
return (min(counter,hpet_tick) * vxtime.quot) >> US_SCALE;
}
#ifdef CONFIG_HPET
static __init int late_hpet_init(void)
{
struct hpet_data hd;
unsigned int ntimer;
if (!hpet_address)
return 0;
memset(&hd, 0, sizeof(hd));
ntimer = hpet_readl(HPET_ID);
ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
ntimer++;
/*
* Register with driver.
* Timer0 and Timer1 is used by platform.
*/
hd.hd_phys_address = hpet_address;
hd.hd_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE);
hd.hd_nirqs = ntimer;
hd.hd_flags = HPET_DATA_PLATFORM;
hpet_reserve_timer(&hd, 0);
#ifdef CONFIG_HPET_EMULATE_RTC
hpet_reserve_timer(&hd, 1);
#endif
hd.hd_irq[0] = HPET_LEGACY_8254;
hd.hd_irq[1] = HPET_LEGACY_RTC;
if (ntimer > 2) {
struct hpet *hpet;
struct hpet_timer *timer;
int i;
hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE);
timer = &hpet->hpet_timers[2];
for (i = 2; i < ntimer; timer++, i++)
hd.hd_irq[i] = (timer->hpet_config &
Tn_INT_ROUTE_CNF_MASK) >>
Tn_INT_ROUTE_CNF_SHIFT;
}
hpet_alloc(&hd);
return 0;
}
fs_initcall(late_hpet_init);
#endif
int hpet_timer_stop_set_go(unsigned long tick)
{
unsigned int cfg;
/*
* Stop the timers and reset the main counter.
*/
cfg = hpet_readl(HPET_CFG);
cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
hpet_writel(cfg, HPET_CFG);
hpet_writel(0, HPET_COUNTER);
hpet_writel(0, HPET_COUNTER + 4);
/*
* Set up timer 0, as periodic with first interrupt to happen at hpet_tick,
* and period also hpet_tick.
*/
if (hpet_use_timer) {
hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL |
HPET_TN_32BIT, HPET_T0_CFG);
hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */
hpet_writel(hpet_tick, HPET_T0_CMP); /* period */
cfg |= HPET_CFG_LEGACY;
}
/*
* Go!
*/
cfg |= HPET_CFG_ENABLE;
hpet_writel(cfg, HPET_CFG);
return 0;
}
int hpet_arch_init(void)
{
unsigned int id;
if (!hpet_address)
return -1;
set_fixmap_nocache(FIX_HPET_BASE, hpet_address);
__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
/*
* Read the period, compute tick and quotient.
*/
id = hpet_readl(HPET_ID);
if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER))
return -1;
hpet_period = hpet_readl(HPET_PERIOD);
if (hpet_period < 100000 || hpet_period > 100000000)
return -1;
hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period;
hpet_use_timer = (id & HPET_ID_LEGSUP);
return hpet_timer_stop_set_go(hpet_tick);
}
int hpet_reenable(void)
{
return hpet_timer_stop_set_go(hpet_tick);
}
/*
* calibrate_tsc() calibrates the processor TSC in a very simple way, comparing
* it to the HPET timer of known frequency.
*/
#define TICK_COUNT 100000000
#define TICK_MIN 5000
/*
* Some platforms take periodic SMI interrupts with 5ms duration. Make sure none
* occurs between the reads of the hpet & TSC.
*/
static void __init read_hpet_tsc(int *hpet, int *tsc)
{
int tsc1, tsc2, hpet1;
do {
tsc1 = get_cycles_sync();
hpet1 = hpet_readl(HPET_COUNTER);
tsc2 = get_cycles_sync();
} while (tsc2 - tsc1 > TICK_MIN);
*hpet = hpet1;
*tsc = tsc2;
}
unsigned int __init hpet_calibrate_tsc(void)
{
int tsc_start, hpet_start;
int tsc_now, hpet_now;
unsigned long flags;
local_irq_save(flags);
read_hpet_tsc(&hpet_start, &tsc_start);
do {
local_irq_disable();
read_hpet_tsc(&hpet_now, &tsc_now);
local_irq_restore(flags);
} while ((tsc_now - tsc_start) < TICK_COUNT &&
(hpet_now - hpet_start) < TICK_COUNT);
return (tsc_now - tsc_start) * 1000000000L
/ ((hpet_now - hpet_start) * hpet_period / 1000);
}
#ifdef CONFIG_HPET_EMULATE_RTC
/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
* is enabled, we support RTC interrupt functionality in software.
* RTC has 3 kinds of interrupts:
* 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
* is updated
* 2) Alarm Interrupt - generate an interrupt at a specific time of day
* 3) Periodic Interrupt - generate periodic interrupt, with frequencies
* 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
* (1) and (2) above are implemented using polling at a frequency of
* 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
* overhead. (DEFAULT_RTC_INT_FREQ)
* For (3), we use interrupts at 64Hz or user specified periodic
* frequency, whichever is higher.
*/
#include <linux/rtc.h>
#define DEFAULT_RTC_INT_FREQ 64
#define RTC_NUM_INTS 1
static unsigned long UIE_on;
static unsigned long prev_update_sec;
static unsigned long AIE_on;
static struct rtc_time alarm_time;
static unsigned long PIE_on;
static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ;
static unsigned long PIE_count;
static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */
static unsigned int hpet_t1_cmp; /* cached comparator register */
int is_hpet_enabled(void)
{
return hpet_address != 0;
}
/*
* Timer 1 for RTC, we do not use periodic interrupt feature,
* even if HPET supports periodic interrupts on Timer 1.
* The reason being, to set up a periodic interrupt in HPET, we need to
* stop the main counter. And if we do that everytime someone diables/enables
* RTC, we will have adverse effect on main kernel timer running on Timer 0.
* So, for the time being, simulate the periodic interrupt in software.
*
* hpet_rtc_timer_init() is called for the first time and during subsequent
* interuppts reinit happens through hpet_rtc_timer_reinit().
*/
int hpet_rtc_timer_init(void)
{
unsigned int cfg, cnt;
unsigned long flags;
if (!is_hpet_enabled())
return 0;
/*
* Set the counter 1 and enable the interrupts.
*/
if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
hpet_rtc_int_freq = PIE_freq;
else
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
local_irq_save(flags);
cnt = hpet_readl(HPET_COUNTER);
cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq);
hpet_writel(cnt, HPET_T1_CMP);
hpet_t1_cmp = cnt;
cfg = hpet_readl(HPET_T1_CFG);
cfg &= ~HPET_TN_PERIODIC;
cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_writel(cfg, HPET_T1_CFG);
local_irq_restore(flags);
return 1;
}
static void hpet_rtc_timer_reinit(void)
{
unsigned int cfg, cnt, ticks_per_int, lost_ints;
if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
cfg = hpet_readl(HPET_T1_CFG);
cfg &= ~HPET_TN_ENABLE;
hpet_writel(cfg, HPET_T1_CFG);
return;
}
if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
hpet_rtc_int_freq = PIE_freq;
else
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
/* It is more accurate to use the comparator value than current count.*/
ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq;
hpet_t1_cmp += ticks_per_int;
hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
/*
* If the interrupt handler was delayed too long, the write above tries
* to schedule the next interrupt in the past and the hardware would
* not interrupt until the counter had wrapped around.
* So we have to check that the comparator wasn't set to a past time.
*/
cnt = hpet_readl(HPET_COUNTER);
if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) {
lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
/* Make sure that, even with the time needed to execute
* this code, the next scheduled interrupt has been moved
* back to the future: */
lost_ints++;
hpet_t1_cmp += lost_ints * ticks_per_int;
hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
if (PIE_on)
PIE_count += lost_ints;
if (printk_ratelimit())
printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
hpet_rtc_int_freq);
}
}
/*
* The functions below are called from rtc driver.
* Return 0 if HPET is not being used.
* Otherwise do the necessary changes and return 1.
*/
int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
{
if (!is_hpet_enabled())
return 0;
if (bit_mask & RTC_UIE)
UIE_on = 0;
if (bit_mask & RTC_PIE)
PIE_on = 0;
if (bit_mask & RTC_AIE)
AIE_on = 0;
return 1;
}
int hpet_set_rtc_irq_bit(unsigned long bit_mask)
{
int timer_init_reqd = 0;
if (!is_hpet_enabled())
return 0;
if (!(PIE_on | AIE_on | UIE_on))
timer_init_reqd = 1;
if (bit_mask & RTC_UIE) {
UIE_on = 1;
}
if (bit_mask & RTC_PIE) {
PIE_on = 1;
PIE_count = 0;
}
if (bit_mask & RTC_AIE) {
AIE_on = 1;
}
if (timer_init_reqd)
hpet_rtc_timer_init();
return 1;
}
int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
{
if (!is_hpet_enabled())
return 0;
alarm_time.tm_hour = hrs;
alarm_time.tm_min = min;
alarm_time.tm_sec = sec;
return 1;
}
int hpet_set_periodic_freq(unsigned long freq)
{
if (!is_hpet_enabled())
return 0;
PIE_freq = freq;
PIE_count = 0;
return 1;
}
int hpet_rtc_dropped_irq(void)
{
if (!is_hpet_enabled())
return 0;
return 1;
}
irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct rtc_time curr_time;
unsigned long rtc_int_flag = 0;
int call_rtc_interrupt = 0;
hpet_rtc_timer_reinit();
if (UIE_on | AIE_on) {
rtc_get_rtc_time(&curr_time);
}
if (UIE_on) {
if (curr_time.tm_sec != prev_update_sec) {
/* Set update int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag = RTC_UF;
prev_update_sec = curr_time.tm_sec;
}
}
if (PIE_on) {
PIE_count++;
if (PIE_count >= hpet_rtc_int_freq/PIE_freq) {
/* Set periodic int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag |= RTC_PF;
PIE_count = 0;
}
}
if (AIE_on) {
if ((curr_time.tm_sec == alarm_time.tm_sec) &&
(curr_time.tm_min == alarm_time.tm_min) &&
(curr_time.tm_hour == alarm_time.tm_hour)) {
/* Set alarm int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag |= RTC_AF;
}
}
if (call_rtc_interrupt) {
rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
rtc_interrupt(rtc_int_flag, dev_id);
}
return IRQ_HANDLED;
}
#endif
static int __init nohpet_setup(char *s)
{
nohpet = 1;
return 1;
}
__setup("nohpet", nohpet_setup);

664
arch/x86_64/kernel/time.c
View file

@ -42,9 +42,10 @@
#include <linux/cpufreq.h>
#include <linux/hpet.h>
#include <asm/apic.h>
#include <asm/hpet.h>
#ifdef CONFIG_CPU_FREQ
static void cpufreq_delayed_get(void);
extern void cpufreq_delayed_get(void);
#endif
extern void i8254_timer_resume(void);
extern int using_apic_timer;
@ -55,22 +56,6 @@ DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
DEFINE_SPINLOCK(i8253_lock);
int nohpet __initdata = 0;
static int notsc __initdata = 0;
#define USEC_PER_TICK (USEC_PER_SEC / HZ)
#define NSEC_PER_TICK (NSEC_PER_SEC / HZ)
#define FSEC_PER_TICK (FSEC_PER_SEC / HZ)
#define NS_SCALE 10 /* 2^10, carefully chosen */
#define US_SCALE 32 /* 2^32, arbitralrily chosen */
unsigned int cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
unsigned long hpet_address;
static unsigned long hpet_period; /* fsecs / HPET clock */
unsigned long hpet_tick; /* HPET clocks / interrupt */
int hpet_use_timer; /* Use counter of hpet for time keeping, otherwise PIT */
unsigned long vxtime_hz = PIT_TICK_RATE;
int report_lost_ticks; /* command line option */
unsigned long long monotonic_base;
@ -81,34 +66,6 @@ volatile unsigned long __jiffies __section_jiffies = INITIAL_JIFFIES;
struct timespec __xtime __section_xtime;
struct timezone __sys_tz __section_sys_tz;
/*
* do_gettimeoffset() returns microseconds since last timer interrupt was
* triggered by hardware. A memory read of HPET is slower than a register read
* of TSC, but much more reliable. It's also synchronized to the timer
* interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a
* timer interrupt has happened already, but vxtime.trigger wasn't updated yet.
* This is not a problem, because jiffies hasn't updated either. They are bound
* together by xtime_lock.
*/
static inline unsigned int do_gettimeoffset_tsc(void)
{
unsigned long t;
unsigned long x;
t = get_cycles_sync();
if (t < vxtime.last_tsc)
t = vxtime.last_tsc; /* hack */
x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE;
return x;
}
static inline unsigned int do_gettimeoffset_hpet(void)
{
/* cap counter read to one tick to avoid inconsistencies */
unsigned long counter = hpet_readl(HPET_COUNTER) - vxtime.last;
return (min(counter,hpet_tick) * vxtime.quot) >> US_SCALE;
}
unsigned int (*do_gettimeoffset)(void) = do_gettimeoffset_tsc;
/*
@ -272,7 +229,7 @@ static void set_rtc_mmss(unsigned long nowtime)
* Note: This function is required to return accurate
* time even in the absence of multiple timer ticks.
*/
static inline unsigned long long cycles_2_ns(unsigned long long cyc);
extern unsigned long long cycles_2_ns(unsigned long long cyc);
unsigned long long monotonic_clock(void)
{
unsigned long seq;
@ -462,40 +419,6 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}
static unsigned int cyc2ns_scale __read_mostly;
static inline void set_cyc2ns_scale(unsigned long cpu_khz)
{
cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / cpu_khz;
}
static inline unsigned long long cycles_2_ns(unsigned long long cyc)
{
return (cyc * cyc2ns_scale) >> NS_SCALE;
}
unsigned long long sched_clock(void)
{
unsigned long a = 0;
#if 0
/* Don't do a HPET read here. Using TSC always is much faster
and HPET may not be mapped yet when the scheduler first runs.
Disadvantage is a small drift between CPUs in some configurations,
but that should be tolerable. */
if (__vxtime.mode == VXTIME_HPET)
return (hpet_readl(HPET_COUNTER) * vxtime.quot) >> US_SCALE;
#endif
/* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
which means it is not completely exact and may not be monotonous between
CPUs. But the errors should be too small to matter for scheduling
purposes. */
rdtscll(a);
return cycles_2_ns(a);
}
static unsigned long get_cmos_time(void)
{
unsigned int year, mon, day, hour, min, sec;
@ -547,164 +470,6 @@ static unsigned long get_cmos_time(void)
return mktime(year, mon, day, hour, min, sec);
}
#ifdef CONFIG_CPU_FREQ
/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
changes.
RED-PEN: On SMP we assume all CPUs run with the same frequency. It's
not that important because current Opteron setups do not support
scaling on SMP anyroads.
Should fix up last_tsc too. Currently gettimeofday in the
first tick after the change will be slightly wrong. */
#include <linux/workqueue.h>
static unsigned int cpufreq_delayed_issched = 0;
static unsigned int cpufreq_init = 0;
static struct work_struct cpufreq_delayed_get_work;
static void handle_cpufreq_delayed_get(struct work_struct *v)
{
unsigned int cpu;
for_each_online_cpu(cpu) {
cpufreq_get(cpu);
}
cpufreq_delayed_issched = 0;
}
/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
* to verify the CPU frequency the timing core thinks the CPU is running
* at is still correct.
*/
static void cpufreq_delayed_get(void)
{
static int warned;
if (cpufreq_init && !cpufreq_delayed_issched) {
cpufreq_delayed_issched = 1;
if (!warned) {
warned = 1;
printk(KERN_DEBUG
"Losing some ticks... checking if CPU frequency changed.\n");
}
schedule_work(&cpufreq_delayed_get_work);
}
}
static unsigned int ref_freq = 0;
static unsigned long loops_per_jiffy_ref = 0;
static unsigned long cpu_khz_ref = 0;
static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
void *data)
{
struct cpufreq_freqs *freq = data;
unsigned long *lpj, dummy;
if (cpu_has(&cpu_data[freq->cpu], X86_FEATURE_CONSTANT_TSC))
return 0;
lpj = &dummy;
if (!(freq->flags & CPUFREQ_CONST_LOOPS))
#ifdef CONFIG_SMP
lpj = &cpu_data[freq->cpu].loops_per_jiffy;
#else
lpj = &boot_cpu_data.loops_per_jiffy;
#endif
if (!ref_freq) {
ref_freq = freq->old;
loops_per_jiffy_ref = *lpj;
cpu_khz_ref = cpu_khz;
}
if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
(val == CPUFREQ_RESUMECHANGE)) {
*lpj =
cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
if (!(freq->flags & CPUFREQ_CONST_LOOPS))
vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
}
set_cyc2ns_scale(cpu_khz_ref);
return 0;
}
static struct notifier_block time_cpufreq_notifier_block = {
.notifier_call = time_cpufreq_notifier
};
static int __init cpufreq_tsc(void)
{
INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get);
if (!cpufreq_register_notifier(&time_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER))
cpufreq_init = 1;
return 0;
}
core_initcall(cpufreq_tsc);
#endif
/*
* calibrate_tsc() calibrates the processor TSC in a very simple way, comparing
* it to the HPET timer of known frequency.
*/
#define TICK_COUNT 100000000
#define TICK_MIN 5000
#define MAX_READ_RETRIES 5
/*
* Some platforms take periodic SMI interrupts with 5ms duration. Make sure none
* occurs between the reads of the hpet & TSC.
*/
static void __init read_hpet_tsc(int *hpet, int *tsc)
{
int tsc1, tsc2, hpet1, retries = 0;
static int msg;
do {
tsc1 = get_cycles_sync();
hpet1 = hpet_readl(HPET_COUNTER);
tsc2 = get_cycles_sync();
} while (tsc2 - tsc1 > TICK_MIN && retries++ < MAX_READ_RETRIES);
if (retries >= MAX_READ_RETRIES && !msg++)
printk(KERN_WARNING
"hpet.c: exceeded max retries to read HPET & TSC\n");
*hpet = hpet1;
*tsc = tsc2;
}
static unsigned int __init hpet_calibrate_tsc(void)
{
int tsc_start, hpet_start;
int tsc_now, hpet_now;
unsigned long flags;
local_irq_save(flags);
local_irq_disable();
read_hpet_tsc(&hpet_start, &tsc_start);
do {
local_irq_disable();
read_hpet_tsc(&hpet_now, &tsc_now);
local_irq_restore(flags);
} while ((tsc_now - tsc_start) < TICK_COUNT &&
(hpet_now - hpet_start) < TICK_COUNT);
return (tsc_now - tsc_start) * 1000000000L
/ ((hpet_now - hpet_start) * hpet_period / 1000);
}
/*
* pit_calibrate_tsc() uses the speaker output (channel 2) of
@ -735,124 +500,6 @@ static unsigned int __init pit_calibrate_tsc(void)
return (end - start) / 50;
}
#ifdef CONFIG_HPET
static __init int late_hpet_init(void)
{
struct hpet_data hd;
unsigned int ntimer;
if (!hpet_address)
return 0;
memset(&hd, 0, sizeof (hd));
ntimer = hpet_readl(HPET_ID);
ntimer = (ntimer & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT;
ntimer++;
/*
* Register with driver.
* Timer0 and Timer1 is used by platform.
*/
hd.hd_phys_address = hpet_address;
hd.hd_address = (void __iomem *)fix_to_virt(FIX_HPET_BASE);
hd.hd_nirqs = ntimer;
hd.hd_flags = HPET_DATA_PLATFORM;
hpet_reserve_timer(&hd, 0);
#ifdef CONFIG_HPET_EMULATE_RTC
hpet_reserve_timer(&hd, 1);
#endif
hd.hd_irq[0] = HPET_LEGACY_8254;
hd.hd_irq[1] = HPET_LEGACY_RTC;
if (ntimer > 2) {
struct hpet *hpet;
struct hpet_timer *timer;
int i;
hpet = (struct hpet *) fix_to_virt(FIX_HPET_BASE);
timer = &hpet->hpet_timers[2];
for (i = 2; i < ntimer; timer++, i++)
hd.hd_irq[i] = (timer->hpet_config &
Tn_INT_ROUTE_CNF_MASK) >>
Tn_INT_ROUTE_CNF_SHIFT;
}
hpet_alloc(&hd);
return 0;
}
fs_initcall(late_hpet_init);
#endif
static int hpet_timer_stop_set_go(unsigned long tick)
{
unsigned int cfg;
/*
* Stop the timers and reset the main counter.
*/
cfg = hpet_readl(HPET_CFG);
cfg &= ~(HPET_CFG_ENABLE | HPET_CFG_LEGACY);
hpet_writel(cfg, HPET_CFG);
hpet_writel(0, HPET_COUNTER);
hpet_writel(0, HPET_COUNTER + 4);
/*
* Set up timer 0, as periodic with first interrupt to happen at hpet_tick,
* and period also hpet_tick.
*/
if (hpet_use_timer) {
hpet_writel(HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL |
HPET_TN_32BIT, HPET_T0_CFG);
hpet_writel(hpet_tick, HPET_T0_CMP); /* next interrupt */
hpet_writel(hpet_tick, HPET_T0_CMP); /* period */
cfg |= HPET_CFG_LEGACY;
}
/*
* Go!
*/
cfg |= HPET_CFG_ENABLE;
hpet_writel(cfg, HPET_CFG);
return 0;
}
static int hpet_init(void)
{
unsigned int id;
if (!hpet_address)
return -1;
set_fixmap_nocache(FIX_HPET_BASE, hpet_address);
__set_fixmap(VSYSCALL_HPET, hpet_address, PAGE_KERNEL_VSYSCALL_NOCACHE);
/*
* Read the period, compute tick and quotient.
*/
id = hpet_readl(HPET_ID);
if (!(id & HPET_ID_VENDOR) || !(id & HPET_ID_NUMBER))
return -1;
hpet_period = hpet_readl(HPET_PERIOD);
if (hpet_period < 100000 || hpet_period > 100000000)
return -1;
hpet_tick = (FSEC_PER_TICK + hpet_period / 2) / hpet_period;
hpet_use_timer = (id & HPET_ID_LEGSUP);
return hpet_timer_stop_set_go(hpet_tick);
}
static int hpet_reenable(void)
{
return hpet_timer_stop_set_go(hpet_tick);
}
#define PIT_MODE 0x43
#define PIT_CH0 0x40
@ -910,7 +557,7 @@ void __init time_init(void)
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
if (!hpet_init())
if (!hpet_arch_init())
vxtime_hz = (FSEC_PER_SEC + hpet_period / 2) / hpet_period;
else
hpet_address = 0;
@ -945,42 +592,6 @@ void __init time_init(void)
#endif
}
static int tsc_unstable = 0;
void mark_tsc_unstable(void)
{
tsc_unstable = 1;
}
EXPORT_SYMBOL_GPL(mark_tsc_unstable);
/*
* Make an educated guess if the TSC is trustworthy and synchronized
* over all CPUs.
*/
__cpuinit int unsynchronized_tsc(void)
{
if (tsc_unstable)
return 1;
#ifdef CONFIG_SMP
if (apic_is_clustered_box())
return 1;
#endif
/* Most intel systems have synchronized TSCs except for
multi node systems */
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
#ifdef CONFIG_ACPI
/* But TSC doesn't tick in C3 so don't use it there */
if (acpi_gbl_FADT.header.length > 0 && acpi_gbl_FADT.C3latency < 1000)
return 1;
#endif
return 0;
}
/* Assume multi socket systems are not synchronized */
return num_present_cpus() > 1;
}
/*
* Decide what mode gettimeofday should use.
*/
@ -1116,270 +727,3 @@ static int time_init_device(void)
}
device_initcall(time_init_device);
#ifdef CONFIG_HPET_EMULATE_RTC
/* HPET in LegacyReplacement Mode eats up RTC interrupt line. When, HPET
* is enabled, we support RTC interrupt functionality in software.
* RTC has 3 kinds of interrupts:
* 1) Update Interrupt - generate an interrupt, every sec, when RTC clock
* is updated
* 2) Alarm Interrupt - generate an interrupt at a specific time of day
* 3) Periodic Interrupt - generate periodic interrupt, with frequencies
* 2Hz-8192Hz (2Hz-64Hz for non-root user) (all freqs in powers of 2)
* (1) and (2) above are implemented using polling at a frequency of
* 64 Hz. The exact frequency is a tradeoff between accuracy and interrupt
* overhead. (DEFAULT_RTC_INT_FREQ)
* For (3), we use interrupts at 64Hz or user specified periodic
* frequency, whichever is higher.
*/
#include <linux/rtc.h>
#define DEFAULT_RTC_INT_FREQ 64
#define RTC_NUM_INTS 1
static unsigned long UIE_on;
static unsigned long prev_update_sec;
static unsigned long AIE_on;
static struct rtc_time alarm_time;
static unsigned long PIE_on;
static unsigned long PIE_freq = DEFAULT_RTC_INT_FREQ;
static unsigned long PIE_count;
static unsigned long hpet_rtc_int_freq; /* RTC interrupt frequency */
static unsigned int hpet_t1_cmp; /* cached comparator register */
int is_hpet_enabled(void)
{
return hpet_address != 0;
}
/*
* Timer 1 for RTC, we do not use periodic interrupt feature,
* even if HPET supports periodic interrupts on Timer 1.
* The reason being, to set up a periodic interrupt in HPET, we need to
* stop the main counter. And if we do that everytime someone diables/enables
* RTC, we will have adverse effect on main kernel timer running on Timer 0.
* So, for the time being, simulate the periodic interrupt in software.
*
* hpet_rtc_timer_init() is called for the first time and during subsequent
* interuppts reinit happens through hpet_rtc_timer_reinit().
*/
int hpet_rtc_timer_init(void)
{
unsigned int cfg, cnt;
unsigned long flags;
if (!is_hpet_enabled())
return 0;
/*
* Set the counter 1 and enable the interrupts.
*/
if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
hpet_rtc_int_freq = PIE_freq;
else
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
local_irq_save(flags);
cnt = hpet_readl(HPET_COUNTER);
cnt += ((hpet_tick*HZ)/hpet_rtc_int_freq);
hpet_writel(cnt, HPET_T1_CMP);
hpet_t1_cmp = cnt;
cfg = hpet_readl(HPET_T1_CFG);
cfg &= ~HPET_TN_PERIODIC;
cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_writel(cfg, HPET_T1_CFG);
local_irq_restore(flags);
return 1;
}
static void hpet_rtc_timer_reinit(void)
{
unsigned int cfg, cnt, ticks_per_int, lost_ints;
if (unlikely(!(PIE_on | AIE_on | UIE_on))) {
cfg = hpet_readl(HPET_T1_CFG);
cfg &= ~HPET_TN_ENABLE;
hpet_writel(cfg, HPET_T1_CFG);
return;
}
if (PIE_on && (PIE_freq > DEFAULT_RTC_INT_FREQ))
hpet_rtc_int_freq = PIE_freq;
else
hpet_rtc_int_freq = DEFAULT_RTC_INT_FREQ;
/* It is more accurate to use the comparator value than current count.*/
ticks_per_int = hpet_tick * HZ / hpet_rtc_int_freq;
hpet_t1_cmp += ticks_per_int;
hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
/*
* If the interrupt handler was delayed too long, the write above tries
* to schedule the next interrupt in the past and the hardware would
* not interrupt until the counter had wrapped around.
* So we have to check that the comparator wasn't set to a past time.
*/
cnt = hpet_readl(HPET_COUNTER);
if (unlikely((int)(cnt - hpet_t1_cmp) > 0)) {
lost_ints = (cnt - hpet_t1_cmp) / ticks_per_int + 1;
/* Make sure that, even with the time needed to execute
* this code, the next scheduled interrupt has been moved
* back to the future: */
lost_ints++;
hpet_t1_cmp += lost_ints * ticks_per_int;
hpet_writel(hpet_t1_cmp, HPET_T1_CMP);
if (PIE_on)
PIE_count += lost_ints;
if (printk_ratelimit())
printk(KERN_WARNING "rtc: lost some interrupts at %ldHz.\n",
hpet_rtc_int_freq);
}
}
/*
* The functions below are called from rtc driver.
* Return 0 if HPET is not being used.
* Otherwise do the necessary changes and return 1.
*/
int hpet_mask_rtc_irq_bit(unsigned long bit_mask)
{
if (!is_hpet_enabled())
return 0;
if (bit_mask & RTC_UIE)
UIE_on = 0;
if (bit_mask & RTC_PIE)
PIE_on = 0;
if (bit_mask & RTC_AIE)
AIE_on = 0;
return 1;
}
int hpet_set_rtc_irq_bit(unsigned long bit_mask)
{
int timer_init_reqd = 0;
if (!is_hpet_enabled())
return 0;
if (!(PIE_on | AIE_on | UIE_on))
timer_init_reqd = 1;
if (bit_mask & RTC_UIE) {
UIE_on = 1;
}
if (bit_mask & RTC_PIE) {
PIE_on = 1;
PIE_count = 0;
}
if (bit_mask & RTC_AIE) {
AIE_on = 1;
}
if (timer_init_reqd)
hpet_rtc_timer_init();
return 1;
}
int hpet_set_alarm_time(unsigned char hrs, unsigned char min, unsigned char sec)
{
if (!is_hpet_enabled())
return 0;
alarm_time.tm_hour = hrs;
alarm_time.tm_min = min;
alarm_time.tm_sec = sec;
return 1;
}
int hpet_set_periodic_freq(unsigned long freq)
{
if (!is_hpet_enabled())
return 0;
PIE_freq = freq;
PIE_count = 0;
return 1;
}
int hpet_rtc_dropped_irq(void)
{
if (!is_hpet_enabled())
return 0;
return 1;
}
irqreturn_t hpet_rtc_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
struct rtc_time curr_time;
unsigned long rtc_int_flag = 0;
int call_rtc_interrupt = 0;
hpet_rtc_timer_reinit();
if (UIE_on | AIE_on) {
rtc_get_rtc_time(&curr_time);
}
if (UIE_on) {
if (curr_time.tm_sec != prev_update_sec) {
/* Set update int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag = RTC_UF;
prev_update_sec = curr_time.tm_sec;
}
}
if (PIE_on) {
PIE_count++;
if (PIE_count >= hpet_rtc_int_freq/PIE_freq) {
/* Set periodic int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag |= RTC_PF;
PIE_count = 0;
}
}
if (AIE_on) {
if ((curr_time.tm_sec == alarm_time.tm_sec) &&
(curr_time.tm_min == alarm_time.tm_min) &&
(curr_time.tm_hour == alarm_time.tm_hour)) {
/* Set alarm int info, call real rtc int routine */
call_rtc_interrupt = 1;
rtc_int_flag |= RTC_AF;
}
}
if (call_rtc_interrupt) {
rtc_int_flag |= (RTC_IRQF | (RTC_NUM_INTS << 8));
rtc_interrupt(rtc_int_flag, dev_id);
}
return IRQ_HANDLED;
}
#endif
static int __init nohpet_setup(char *s)
{
nohpet = 1;
return 1;
}
__setup("nohpet", nohpet_setup);
int __init notsc_setup(char *s)
{
notsc = 1;
return 1;
}
__setup("notsc", notsc_setup);

212
arch/x86_64/kernel/tsc.c Normal file
View file

@ -0,0 +1,212 @@
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/clocksource.h>
#include <linux/time.h>
#include <linux/acpi.h>
#include <linux/cpufreq.h>
#include <asm/timex.h>
int notsc __initdata = 0;
unsigned int cpu_khz; /* TSC clocks / usec, not used here */
EXPORT_SYMBOL(cpu_khz);
/*
* do_gettimeoffset() returns microseconds since last timer interrupt was
* triggered by hardware. A memory read of HPET is slower than a register read
* of TSC, but much more reliable. It's also synchronized to the timer
* interrupt. Note that do_gettimeoffset() may return more than hpet_tick, if a
* timer interrupt has happened already, but vxtime.trigger wasn't updated yet.
* This is not a problem, because jiffies hasn't updated either. They are bound
* together by xtime_lock.
*/
unsigned int do_gettimeoffset_tsc(void)
{
unsigned long t;
unsigned long x;
t = get_cycles_sync();
if (t < vxtime.last_tsc)
t = vxtime.last_tsc; /* hack */
x = ((t - vxtime.last_tsc) * vxtime.tsc_quot) >> US_SCALE;
return x;
}
static unsigned int cyc2ns_scale __read_mostly;
void set_cyc2ns_scale(unsigned long khz)
{
cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / khz;
}
unsigned long long cycles_2_ns(unsigned long long cyc)
{
return (cyc * cyc2ns_scale) >> NS_SCALE;
}
unsigned long long sched_clock(void)
{
unsigned long a = 0;
/* Could do CPU core sync here. Opteron can execute rdtsc speculatively,
* which means it is not completely exact and may not be monotonous
* between CPUs. But the errors should be too small to matter for
* scheduling purposes.
*/
rdtscll(a);
return cycles_2_ns(a);
}
#ifdef CONFIG_CPU_FREQ
/* Frequency scaling support. Adjust the TSC based timer when the cpu frequency
* changes.
*
* RED-PEN: On SMP we assume all CPUs run with the same frequency. It's
* not that important because current Opteron setups do not support
* scaling on SMP anyroads.
*
* Should fix up last_tsc too. Currently gettimeofday in the
* first tick after the change will be slightly wrong.
*/
#include <linux/workqueue.h>
static unsigned int cpufreq_delayed_issched = 0;
static unsigned int cpufreq_init = 0;
static struct work_struct cpufreq_delayed_get_work;
static void handle_cpufreq_delayed_get(struct work_struct *v)
{
unsigned int cpu;
for_each_online_cpu(cpu) {
cpufreq_get(cpu);
}
cpufreq_delayed_issched = 0;
}
/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
* to verify the CPU frequency the timing core thinks the CPU is running
* at is still correct.
*/
void cpufreq_delayed_get(void)
{
static int warned;
if (cpufreq_init && !cpufreq_delayed_issched) {
cpufreq_delayed_issched = 1;
if (!warned) {
warned = 1;
printk(KERN_DEBUG "Losing some ticks... "
"checking if CPU frequency changed.\n");
}
schedule_work(&cpufreq_delayed_get_work);
}
}
static unsigned int ref_freq = 0;
static unsigned long loops_per_jiffy_ref = 0;
static unsigned long cpu_khz_ref = 0;
static int time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
void *data)
{
struct cpufreq_freqs *freq = data;
unsigned long *lpj, dummy;
if (cpu_has(&cpu_data[freq->cpu], X86_FEATURE_CONSTANT_TSC))
return 0;
lpj = &dummy;
if (!(freq->flags & CPUFREQ_CONST_LOOPS))
#ifdef CONFIG_SMP
lpj = &cpu_data[freq->cpu].loops_per_jiffy;
#else
lpj = &boot_cpu_data.loops_per_jiffy;
#endif
if (!ref_freq) {
ref_freq = freq->old;
loops_per_jiffy_ref = *lpj;
cpu_khz_ref = cpu_khz;
}
if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
(val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
(val == CPUFREQ_RESUMECHANGE)) {
*lpj =
cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
if (!(freq->flags & CPUFREQ_CONST_LOOPS))
vxtime.tsc_quot = (USEC_PER_MSEC << US_SCALE) / cpu_khz;
}
set_cyc2ns_scale(cpu_khz_ref);
return 0;
}
static struct notifier_block time_cpufreq_notifier_block = {
.notifier_call = time_cpufreq_notifier
};
static int __init cpufreq_tsc(void)
{
INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get);
if (!cpufreq_register_notifier(&time_cpufreq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER))
cpufreq_init = 1;
return 0;
}
core_initcall(cpufreq_tsc);
#endif
static int tsc_unstable = 0;
void mark_tsc_unstable(void)
{
tsc_unstable = 1;
}
EXPORT_SYMBOL_GPL(mark_tsc_unstable);
/*
* Make an educated guess if the TSC is trustworthy and synchronized
* over all CPUs.
*/
__cpuinit int unsynchronized_tsc(void)
{
if (tsc_unstable)
return 1;
#ifdef CONFIG_SMP
if (apic_is_clustered_box())
return 1;
#endif
/* Most intel systems have synchronized TSCs except for
multi node systems */
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) {
#ifdef CONFIG_ACPI
/* But TSC doesn't tick in C3 so don't use it there */
if (acpi_gbl_FADT.header.length > 0 && acpi_gbl_FADT.C3latency < 1000)
return 1;
#endif
return 0;
}
/* Assume multi socket systems are not synchronized */
return num_present_cpus() > 1;
}
int __init notsc_setup(char *s)
{
notsc = 1;
return 1;
}
__setup("notsc", notsc_setup);

6
include/asm-x86_64/hpet.h
View file

@ -56,9 +56,15 @@
extern int is_hpet_enabled(void);
extern int hpet_rtc_timer_init(void);
extern int apic_is_clustered_box(void);
extern int hpet_arch_init(void);
extern int hpet_timer_stop_set_go(unsigned long tick);
extern int hpet_reenable(void);
extern unsigned int hpet_calibrate_tsc(void);
extern int hpet_use_timer;
extern unsigned long hpet_address;
extern unsigned long hpet_period;
extern unsigned long hpet_tick;
#ifdef CONFIG_HPET_EMULATE_RTC
extern int hpet_mask_rtc_irq_bit(unsigned long bit_mask);

11
include/asm-x86_64/timex.h
View file

@ -20,6 +20,17 @@
extern int read_current_timer(unsigned long *timer_value);
#define ARCH_HAS_READ_CURRENT_TIMER 1
#define USEC_PER_TICK (USEC_PER_SEC / HZ)
#define NSEC_PER_TICK (NSEC_PER_SEC / HZ)
#define FSEC_PER_TICK (FSEC_PER_SEC / HZ)
#define NS_SCALE 10 /* 2^10, carefully chosen */
#define US_SCALE 32 /* 2^32, arbitralrily chosen */
extern struct vxtime_data vxtime;
extern unsigned int do_gettimeoffset_hpet(void);
extern unsigned int do_gettimeoffset_tsc(void);
extern void set_cyc2ns_scale(unsigned long khz);
extern int notsc;
#endif

2
kernel/tsacct.c
View file

@ -22,8 +22,6 @@
#include <linux/acct.h>
#include <linux/jiffies.h>
#define USEC_PER_TICK (USEC_PER_SEC/HZ)
/*
* fill in basic accounting fields
*/