#include <linux/sched.h>
#include <linux/clocksource.h>
#include <linux/workqueue.h>
+#include <linux/delay.h>
#include <linux/cpufreq.h>
#include <linux/jiffies.h>
#include <linux/init.h>
#include "mach_timer.h"
-/* native_sched_clock() is called before tsc_init(), so
- we must start with the TSC soft disabled to prevent
- erroneous rdtsc usage on !cpu_has_tsc processors */
-static int tsc_disabled = -1;
-
-/*
- * On some systems the TSC frequency does not
- * change with the cpu frequency. So we need
- * an extra value to store the TSC freq
- */
-unsigned int tsc_khz;
-EXPORT_SYMBOL_GPL(tsc_khz);
-
-#ifdef CONFIG_X86_TSC
-static int __init tsc_setup(char *str)
-{
- printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
- "cannot disable TSC completely.\n");
- tsc_disabled = 1;
- return 1;
-}
-#else
-/*
- * disable flag for tsc. Takes effect by clearing the TSC cpu flag
- * in cpu/common.c
- */
-static int __init tsc_setup(char *str)
-{
- setup_clear_cpu_cap(X86_FEATURE_TSC);
- return 1;
-}
-#endif
-
-__setup("notsc", tsc_setup);
-
-/*
- * code to mark and check if the TSC is unstable
- * due to cpufreq or due to unsynced TSCs
- */
-static int tsc_unstable;
-
-int check_tsc_unstable(void)
-{
- return tsc_unstable;
-}
-EXPORT_SYMBOL_GPL(check_tsc_unstable);
-
-/* Accelerators for sched_clock()
- * convert from cycles(64bits) => nanoseconds (64bits)
- * basic equation:
- * ns = cycles / (freq / ns_per_sec)
- * ns = cycles * (ns_per_sec / freq)
- * ns = cycles * (10^9 / (cpu_khz * 10^3))
- * ns = cycles * (10^6 / cpu_khz)
- *
- * Then we use scaling math (suggested by george@mvista.com) to get:
- * ns = cycles * (10^6 * SC / cpu_khz) / SC
- * ns = cycles * cyc2ns_scale / SC
- *
- * And since SC is a constant power of two, we can convert the div
- * into a shift.
- *
- * We can use khz divisor instead of mhz to keep a better precision, since
- * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
- * (mathieu.desnoyers@polymtl.ca)
- *
- * -johnstul@us.ibm.com "math is hard, lets go shopping!"
- */
-
-DEFINE_PER_CPU(unsigned long, cyc2ns);
-
-static void set_cyc2ns_scale(unsigned long cpu_khz, int cpu)
-{
- unsigned long long tsc_now, ns_now;
- unsigned long flags, *scale;
-
- local_irq_save(flags);
- sched_clock_idle_sleep_event();
-
- scale = &per_cpu(cyc2ns, cpu);
-
- rdtscll(tsc_now);
- ns_now = __cycles_2_ns(tsc_now);
-
- if (cpu_khz)
- *scale = (NSEC_PER_MSEC << CYC2NS_SCALE_FACTOR)/cpu_khz;
-
- /*
- * Start smoothly with the new frequency:
- */
- sched_clock_idle_wakeup_event(0);
- local_irq_restore(flags);
-}
-
-/*
- * Scheduler clock - returns current time in nanosec units.
- */
-unsigned long long native_sched_clock(void)
-{
- unsigned long long this_offset;
-
- /*
- * Fall back to jiffies if there's no TSC available:
- * ( But note that we still use it if the TSC is marked
- * unstable. We do this because unlike Time Of Day,
- * the scheduler clock tolerates small errors and it's
- * very important for it to be as fast as the platform
- * can achive it. )
- */
- if (unlikely(tsc_disabled))
- /* No locking but a rare wrong value is not a big deal: */
- return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
-
- /* read the Time Stamp Counter: */
- rdtscll(this_offset);
-
- /* return the value in ns */
- return cycles_2_ns(this_offset);
-}
-
-/* We need to define a real function for sched_clock, to override the
- weak default version */
-#ifdef CONFIG_PARAVIRT
-unsigned long long sched_clock(void)
-{
- return paravirt_sched_clock();
-}
-#else
-unsigned long long sched_clock(void)
- __attribute__((alias("native_sched_clock")));
-#endif
-
-unsigned long native_calculate_cpu_khz(void)
-{
- unsigned long long start, end;
- unsigned long count;
- u64 delta64 = (u64)ULLONG_MAX;
- int i;
- unsigned long flags;
-
- local_irq_save(flags);
-
- /* run 3 times to ensure the cache is warm and to get an accurate reading */
- for (i = 0; i < 3; i++) {
- mach_prepare_counter();
- rdtscll(start);
- mach_countup(&count);
- rdtscll(end);
-
- /*
- * Error: ECTCNEVERSET
- * The CTC wasn't reliable: we got a hit on the very first read,
- * or the CPU was so fast/slow that the quotient wouldn't fit in
- * 32 bits..
- */
- if (count <= 1)
- continue;
-
- /* cpu freq too slow: */
- if ((end - start) <= CALIBRATE_TIME_MSEC)
- continue;
-
- /*
- * We want the minimum time of all runs in case one of them
- * is inaccurate due to SMI or other delay
- */
- delta64 = min(delta64, (end - start));
- }
-
- /* cpu freq too fast (or every run was bad): */
- if (delta64 > (1ULL<<32))
- goto err;
-
- delta64 += CALIBRATE_TIME_MSEC/2; /* round for do_div */
- do_div(delta64,CALIBRATE_TIME_MSEC);
-
- local_irq_restore(flags);
- return (unsigned long)delta64;
-err:
- local_irq_restore(flags);
- return 0;
-}
-
-int recalibrate_cpu_khz(void)
-{
-#ifndef CONFIG_SMP
- unsigned long cpu_khz_old = cpu_khz;
-
- if (cpu_has_tsc) {
- cpu_khz = calculate_cpu_khz();
- tsc_khz = 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);
-
-#ifdef CONFIG_CPU_FREQ
-
-/*
- * if the CPU frequency is scaled, TSC-based delays will need a different
- * loops_per_jiffy value to function properly.
- */
-static unsigned int ref_freq;
-static unsigned long loops_per_jiffy_ref;
-static unsigned long cpu_khz_ref;
-
-static int
-time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
-{
- struct cpufreq_freqs *freq = data;
-
- if (!ref_freq) {
- if (!freq->old){
- ref_freq = freq->new;
- return 0;
- }
- ref_freq = freq->old;
- loops_per_jiffy_ref = cpu_data(freq->cpu).loops_per_jiffy;
- cpu_khz_ref = cpu_khz;
- }
-
- if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
- (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);
-
- if (cpu_khz) {
-
- if (num_online_cpus() == 1)
- cpu_khz = cpufreq_scale(cpu_khz_ref,
- ref_freq, freq->new);
- if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
- tsc_khz = cpu_khz;
- set_cyc2ns_scale(cpu_khz, freq->cpu);
- /*
- * TSC based sched_clock turns
- * to junk w/ cpufreq
- */
- mark_tsc_unstable("cpufreq changes");
- }
- }
- }
-
- return 0;
-}
-
-static struct notifier_block time_cpufreq_notifier_block = {
- .notifier_call = time_cpufreq_notifier
-};
-
-static int __init cpufreq_tsc(void)
-{
- return cpufreq_register_notifier(&time_cpufreq_notifier_block,
- CPUFREQ_TRANSITION_NOTIFIER);
-}
-core_initcall(cpufreq_tsc);
-
-#endif
+extern int tsc_unstable;
+extern int tsc_disabled;
/* clock source code */
-static unsigned long current_tsc_khz;
static struct clocksource clocksource_tsc;
/*
void __init tsc_init(void)
{
int cpu;
+ u64 lpj;
if (!cpu_has_tsc || tsc_disabled > 0)
return;
return;
}
+ lpj = ((u64)tsc_khz * 1000);
+ do_div(lpj, HZ);
+ lpj_fine = lpj;
+
/* now allow native_sched_clock() to use rdtsc */
tsc_disabled = 0;
unsynchronized_tsc();
check_geode_tsc_reliable();
- current_tsc_khz = tsc_khz;
- clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
- clocksource_tsc.shift);
+ clocksource_tsc.mult = clocksource_khz2mult(tsc_khz,
+ clocksource_tsc.shift);
/* lower the rating if we already know its unstable: */
if (check_tsc_unstable()) {
clocksource_tsc.rating = 0;
projects / linux-2.6-omap-h63xx.git / blobdiff