+++ /dev/null
-#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>
-
-static int notsc __initdata = 0;
-
-unsigned int cpu_khz; /* TSC clocks / usec, not used here */
-EXPORT_SYMBOL(cpu_khz);
-unsigned int tsc_khz;
-EXPORT_SYMBOL(tsc_khz);
-
-static unsigned int cyc2ns_scale __read_mostly;
-
-void set_cyc2ns_scale(unsigned long khz)
-{
- cyc2ns_scale = (NSEC_PER_MSEC << NS_SCALE) / khz;
-}
-
-static 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);
-}
-
-static int tsc_unstable;
-
-inline int check_tsc_unstable(void)
-{
- return tsc_unstable;
-}
-#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.
- */
-
-static unsigned int ref_freq;
-static unsigned long loops_per_jiffy_ref;
-static unsigned long tsc_khz_ref;
-
-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;
- tsc_khz_ref = tsc_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);
-
- tsc_khz = cpufreq_scale(tsc_khz_ref, ref_freq, freq->new);
- if (!(freq->flags & CPUFREQ_CONST_LOOPS))
- mark_tsc_unstable("cpufreq changes");
- }
-
- set_cyc2ns_scale(tsc_khz_ref);
-
- return 0;
-}
-
-static struct notifier_block time_cpufreq_notifier_block = {
- .notifier_call = time_cpufreq_notifier
-};
-
-static int __init cpufreq_tsc(void)
-{
- cpufreq_register_notifier(&time_cpufreq_notifier_block,
- CPUFREQ_TRANSITION_NOTIFIER);
- return 0;
-}
-
-core_initcall(cpufreq_tsc);
-
-#endif
-
-/*
- * 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);
-
-
-/* clock source code: */
-static cycle_t read_tsc(void)
-{
- cycle_t ret = (cycle_t)get_cycles_sync();
- return ret;
-}
-
-static cycle_t __vsyscall_fn vread_tsc(void)
-{
- cycle_t ret = (cycle_t)get_cycles_sync();
- return ret;
-}
-
-static struct clocksource clocksource_tsc = {
- .name = "tsc",
- .rating = 300,
- .read = read_tsc,
- .mask = CLOCKSOURCE_MASK(64),
- .shift = 22,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS |
- CLOCK_SOURCE_MUST_VERIFY,
- .vread = vread_tsc,
-};
-
-void mark_tsc_unstable(char *reason)
-{
- if (!tsc_unstable) {
- tsc_unstable = 1;
- printk("Marking TSC unstable due to %s\n", reason);
- /* Change only the rating, when not registered */
- if (clocksource_tsc.mult)
- clocksource_change_rating(&clocksource_tsc, 0);
- else
- clocksource_tsc.rating = 0;
- }
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
-void __init init_tsc_clocksource(void)
-{
- if (!notsc) {
- clocksource_tsc.mult = clocksource_khz2mult(tsc_khz,
- clocksource_tsc.shift);
- if (check_tsc_unstable())
- clocksource_tsc.rating = 0;
-
- clocksource_register(&clocksource_tsc);
- }
-}
git.openpandora.org / pandora-kernel.git / blobdiff