/*
* This code largely moved from arch/i386/kernel/time.c.
* See comments there for proper credits.
+ *
+ * 2004-06-25 Jesper Juhl
+ * moved mark_offset_tsc below cpufreq_delayed_get to avoid gcc 3.4
+ * failing to inline.
*/
#include <linux/spinlock.h>
#ifdef CONFIG_HPET_TIMER
static unsigned long hpet_usec_quotient;
static unsigned long hpet_last;
-struct timer_opts timer_tsc;
+static struct timer_opts timer_tsc;
#endif
+static inline void cpufreq_delayed_get(void);
+
int tsc_disable __initdata = 0;
extern spinlock_t i8253_lock;
return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
}
-
static int count2; /* counter for mark_offset_tsc() */
/* Cached *multiplier* to convert TSC counts to microseconds.
return cycles_2_ns(this_offset);
}
-
-static void mark_offset_tsc(void)
-{
- unsigned long lost,delay;
- unsigned long delta = last_tsc_low;
- int count;
- int countmp;
- static int count1 = 0;
- unsigned long long this_offset, last_offset;
- static int lost_count = 0;
-
- write_seqlock(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- /*
- * It is important that these two operations happen almost at
- * the same time. We do the RDTSC stuff first, since it's
- * faster. To avoid any inconsistencies, we need interrupts
- * disabled locally.
- */
-
- /*
- * Interrupts are just disabled locally since the timer irq
- * has the SA_INTERRUPT flag set. -arca
- */
-
- /* read Pentium cycle counter */
-
- rdtsc(last_tsc_low, last_tsc_high);
-
- spin_lock(&i8253_lock);
- outb_p(0x00, PIT_MODE); /* latch the count ASAP */
-
- count = inb_p(PIT_CH0); /* read the latched count */
- count |= inb(PIT_CH0) << 8;
-
- /*
- * VIA686a test code... reset the latch if count > max + 1
- * from timer_pit.c - cjb
- */
- if (count > LATCH) {
- outb_p(0x34, PIT_MODE);
- outb_p(LATCH & 0xff, PIT_CH0);
- outb(LATCH >> 8, PIT_CH0);
- count = LATCH - 1;
- }
-
- spin_unlock(&i8253_lock);
-
- if (pit_latch_buggy) {
- /* get center value of last 3 time lutch */
- if ((count2 >= count && count >= count1)
- || (count1 >= count && count >= count2)) {
- count2 = count1; count1 = count;
- } else if ((count1 >= count2 && count2 >= count)
- || (count >= count2 && count2 >= count1)) {
- countmp = count;count = count2;
- count2 = count1;count1 = countmp;
- } else {
- count2 = count1; count1 = count; count = count1;
- }
- }
-
- /* lost tick compensation */
- delta = last_tsc_low - delta;
- {
- register unsigned long eax, edx;
- eax = delta;
- __asm__("mull %2"
- :"=a" (eax), "=d" (edx)
- :"rm" (fast_gettimeoffset_quotient),
- "0" (eax));
- delta = edx;
- }
- delta += delay_at_last_interrupt;
- lost = delta/(1000000/HZ);
- delay = delta%(1000000/HZ);
- if (lost >= 2) {
- jiffies_64 += lost-1;
-
- /* sanity check to ensure we're not always losing ticks */
- if (lost_count++ > 100) {
- printk(KERN_WARNING "Losing too many ticks!\n");
- printk(KERN_WARNING "TSC cannot be used as a timesource. \n");
- printk(KERN_WARNING "Possible reasons for this are:\n");
- printk(KERN_WARNING " You're running with Speedstep,\n");
- printk(KERN_WARNING " You don't have DMA enabled for your hard disk (see hdparm),\n");
- printk(KERN_WARNING " Incorrect TSC synchronization on an SMP system (see dmesg).\n");
- printk(KERN_WARNING "Falling back to a sane timesource now.\n");
-
- clock_fallback();
- }
- } else
- lost_count = 0;
- /* update the monotonic base value */
- this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- monotonic_base += cycles_2_ns(this_offset - last_offset);
- write_sequnlock(&monotonic_lock);
-
- /* calculate delay_at_last_interrupt */
- count = ((LATCH-1) - count) * TICK_SIZE;
- delay_at_last_interrupt = (count + LATCH/2) / LATCH;
-
- /* catch corner case where tick rollover occured
- * between tsc and pit reads (as noted when
- * usec delta is > 90% # of usecs/tick)
- */
- if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
- jiffies_64++;
-}
-
static void delay_tsc(unsigned long loops)
{
unsigned long bclock, now;
#ifdef CONFIG_CPU_FREQ
+#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(void *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 inline void cpufreq_delayed_get(void)
+{
+ if (cpufreq_init && !cpufreq_delayed_issched) {
+ cpufreq_delayed_issched = 1;
+ printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n");
+ schedule_work(&cpufreq_delayed_get_work);
+ }
+}
+
/* If the CPU frequency is scaled, TSC-based delays will need a different
- * loops_per_jiffy value to function properly. An exception to this
- * are modern Intel Pentium 4 processors, where the TSC runs at a constant
- * speed independent of frequency scaling.
+ * loops_per_jiffy value to function properly.
*/
static unsigned int ref_freq = 0;
static unsigned long loops_per_jiffy_ref = 0;
-static unsigned int variable_tsc = 1;
#ifndef CONFIG_SMP
static unsigned long fast_gettimeoffset_ref = 0;
{
struct cpufreq_freqs *freq = data;
- write_seqlock_irq(&xtime_lock);
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_seqlock_irq(&xtime_lock);
if (!ref_freq) {
ref_freq = freq->old;
loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
}
if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
- (val == CPUFREQ_POSTCHANGE && freq->old > freq->new)) {
- if (variable_tsc)
+ (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+ (val == CPUFREQ_RESUMECHANGE)) {
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS))
cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
#ifndef CONFIG_SMP
if (cpu_khz)
cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
if (use_tsc) {
- if (variable_tsc) {
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq);
set_cyc2ns_scale(cpu_khz/1000);
}
}
#endif
}
- write_sequnlock_irq(&xtime_lock);
+
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_sequnlock_irq(&xtime_lock);
return 0;
}
static int __init cpufreq_tsc(void)
{
- /* P4 and above CPU TSC freq doesn't change when CPU frequency changes*/
- if ((boot_cpu_data.x86 >= 15) && (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL))
- variable_tsc = 0;
-
- return cpufreq_register_notifier(&time_cpufreq_notifier_block, CPUFREQ_TRANSITION_NOTIFIER);
+ int ret;
+ INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);
+ ret = cpufreq_register_notifier(&time_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ if (!ret)
+ cpufreq_init = 1;
+ return ret;
}
core_initcall(cpufreq_tsc);
+#else /* CONFIG_CPU_FREQ */
+static inline void cpufreq_delayed_get(void) { return; }
#endif
+int recalibrate_cpu_khz(void)
+{
+#ifndef CONFIG_SMP
+ unsigned long cpu_khz_old = cpu_khz;
+
+ if (cpu_has_tsc) {
+ init_cpu_khz();
+ cpu_data[0].loops_per_jiffy =
+ cpufreq_scale(cpu_data[0].loops_per_jiffy,
+ cpu_khz_old,
+ cpu_khz);
+ return 0;
+ } else
+ return -ENODEV;
+#else
+ return -ENODEV;
+#endif
+}
+EXPORT_SYMBOL(recalibrate_cpu_khz);
+
+static void mark_offset_tsc(void)
+{
+ unsigned long lost,delay;
+ unsigned long delta = last_tsc_low;
+ int count;
+ int countmp;
+ static int count1 = 0;
+ unsigned long long this_offset, last_offset;
+ static int lost_count = 0;
+
+ write_seqlock(&monotonic_lock);
+ last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ /*
+ * It is important that these two operations happen almost at
+ * the same time. We do the RDTSC stuff first, since it's
+ * faster. To avoid any inconsistencies, we need interrupts
+ * disabled locally.
+ */
+
+ /*
+ * Interrupts are just disabled locally since the timer irq
+ * has the SA_INTERRUPT flag set. -arca
+ */
+
+ /* read Pentium cycle counter */
+
+ rdtsc(last_tsc_low, last_tsc_high);
+
+ spin_lock(&i8253_lock);
+ outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+
+ count = inb_p(PIT_CH0); /* read the latched count */
+ count |= inb(PIT_CH0) << 8;
+
+ /*
+ * VIA686a test code... reset the latch if count > max + 1
+ * from timer_pit.c - cjb
+ */
+ if (count > LATCH) {
+ outb_p(0x34, PIT_MODE);
+ outb_p(LATCH & 0xff, PIT_CH0);
+ outb(LATCH >> 8, PIT_CH0);
+ count = LATCH - 1;
+ }
+
+ spin_unlock(&i8253_lock);
+
+ if (pit_latch_buggy) {
+ /* get center value of last 3 time lutch */
+ if ((count2 >= count && count >= count1)
+ || (count1 >= count && count >= count2)) {
+ count2 = count1; count1 = count;
+ } else if ((count1 >= count2 && count2 >= count)
+ || (count >= count2 && count2 >= count1)) {
+ countmp = count;count = count2;
+ count2 = count1;count1 = countmp;
+ } else {
+ count2 = count1; count1 = count; count = count1;
+ }
+ }
+
+ /* lost tick compensation */
+ delta = last_tsc_low - delta;
+ {
+ register unsigned long eax, edx;
+ eax = delta;
+ __asm__("mull %2"
+ :"=a" (eax), "=d" (edx)
+ :"rm" (fast_gettimeoffset_quotient),
+ "0" (eax));
+ delta = edx;
+ }
+ delta += delay_at_last_interrupt;
+ lost = delta/(1000000/HZ);
+ delay = delta%(1000000/HZ);
+ if (lost >= 2) {
+ jiffies_64 += lost-1;
+
+ /* sanity check to ensure we're not always losing ticks */
+ if (lost_count++ > 100) {
+ printk(KERN_WARNING "Losing too many ticks!\n");
+ printk(KERN_WARNING "TSC cannot be used as a timesource. \n");
+ printk(KERN_WARNING "Possible reasons for this are:\n");
+ printk(KERN_WARNING " You're running with Speedstep,\n");
+ printk(KERN_WARNING " You don't have DMA enabled for your hard disk (see hdparm),\n");
+ printk(KERN_WARNING " Incorrect TSC synchronization on an SMP system (see dmesg).\n");
+ printk(KERN_WARNING "Falling back to a sane timesource now.\n");
+
+ clock_fallback();
+ }
+ /* ... but give the TSC a fair chance */
+ if (lost_count > 25)
+ cpufreq_delayed_get();
+ } else
+ lost_count = 0;
+ /* update the monotonic base value */
+ this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
+ monotonic_base += cycles_2_ns(this_offset - last_offset);
+ write_sequnlock(&monotonic_lock);
+
+ /* calculate delay_at_last_interrupt */
+ count = ((LATCH-1) - count) * TICK_SIZE;
+ delay_at_last_interrupt = (count + LATCH/2) / LATCH;
+
+ /* catch corner case where tick rollover occured
+ * between tsc and pit reads (as noted when
+ * usec delta is > 90% # of usecs/tick)
+ */
+ if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
+ jiffies_64++;
+}
static int __init init_tsc(char* override)
{
if (cpu_has_tsc) {
unsigned long tsc_quotient;
#ifdef CONFIG_HPET_TIMER
- if (is_hpet_enabled()){
+ if (is_hpet_enabled() && hpet_use_timer) {
unsigned long result, remain;
printk("Using TSC for gettimeofday\n");
tsc_quotient = calibrate_tsc_hpet(NULL);
/************************************************************/
/* tsc timer_opts struct */
-struct timer_opts timer_tsc = {
- .name = "tsc",
- .init = init_tsc,
- .mark_offset = mark_offset_tsc,
- .get_offset = get_offset_tsc,
- .monotonic_clock = monotonic_clock_tsc,
+static struct timer_opts timer_tsc = {
+ .name = "tsc",
+ .mark_offset = mark_offset_tsc,
+ .get_offset = get_offset_tsc,
+ .monotonic_clock = monotonic_clock_tsc,
.delay = delay_tsc,
};
+
+struct init_timer_opts __initdata timer_tsc_init = {
+ .init = init_tsc,
+ .opts = &timer_tsc,
+};
git://git.onelab.eu / linux-2.6.git / blobdiff