#include <asm/delay.h>
#include <asm/tsc.h>
#include <asm/io.h>
+#include <asm/timer.h>
#include "mach_timer.h"
return tsc_unstable;
}
-void mark_tsc_unstable(void)
-{
- tsc_unstable = 1;
-}
-EXPORT_SYMBOL_GPL(mark_tsc_unstable);
-
/* Accellerators for sched_clock()
* convert from cycles(64bits) => nanoseconds (64bits)
* basic equation:
{
unsigned long long this_offset;
- if (unlikely(custom_sched_clock))
- return (*custom_sched_clock)();
-
/*
* Fall back to jiffies if there's no TSC available:
*/
return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
/* read the Time Stamp Counter: */
- rdtscll(this_offset);
+ get_scheduled_cycles(this_offset);
/* return the value in ns */
return cycles_2_ns(this_offset);
}
-static unsigned long calculate_cpu_khz(void)
+unsigned long native_calculate_cpu_khz(void)
{
unsigned long long start, end;
unsigned long count;
/* clock source code */
static unsigned long current_tsc_khz = 0;
-static int tsc_update_callback(void);
static cycle_t read_tsc(void)
{
.mask = CLOCKSOURCE_MASK(64),
.mult = 0, /* to be set */
.shift = 22,
- .update_callback = tsc_update_callback,
- .is_continuous = 1,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS |
+ CLOCK_SOURCE_MUST_VERIFY,
};
-static int tsc_update_callback(void)
+void mark_tsc_unstable(void)
{
- int change = 0;
-
- /* check to see if we should switch to the safe clocksource: */
- if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
- clocksource_change_rating(&clocksource_tsc, 0);
- change = 1;
- }
-
- /* only update if tsc_khz has changed: */
- if (current_tsc_khz != tsc_khz) {
- current_tsc_khz = tsc_khz;
- clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
- clocksource_tsc.shift);
- change = 1;
+ if (!tsc_unstable) {
+ tsc_unstable = 1;
+ /* Can be called before registration */
+ if (clocksource_tsc.mult)
+ clocksource_change_rating(&clocksource_tsc, 0);
+ else
+ clocksource_tsc.rating = 0;
}
-
- return change;
}
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
{
printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
d->ident);
- mark_tsc_unstable();
+ tsc_unstable = 1;
return 0;
}
{}
};
-#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */
-static struct timer_list verify_tsc_freq_timer;
-
-/* XXX - Probably should add locking */
-static void verify_tsc_freq(unsigned long unused)
-{
- static u64 last_tsc;
- static unsigned long last_jiffies;
-
- u64 now_tsc, interval_tsc;
- unsigned long now_jiffies, interval_jiffies;
-
-
- if (check_tsc_unstable())
- return;
-
- rdtscll(now_tsc);
- now_jiffies = jiffies;
-
- if (!last_jiffies) {
- goto out;
- }
-
- interval_jiffies = now_jiffies - last_jiffies;
- interval_tsc = now_tsc - last_tsc;
- interval_tsc *= HZ;
- do_div(interval_tsc, cpu_khz*1000);
-
- if (interval_tsc < (interval_jiffies * 3 / 4)) {
- printk("TSC appears to be running slowly. "
- "Marking it as unstable\n");
- mark_tsc_unstable();
- return;
- }
-
-out:
- last_tsc = now_tsc;
- last_jiffies = now_jiffies;
- /* set us up to go off on the next interval: */
- mod_timer(&verify_tsc_freq_timer,
- jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
-}
-
/*
* Make an educated guess if the TSC is trustworthy and synchronized
* over all CPUs.
* Intel systems are normally all synchronized.
* Exceptions must mark TSC as unstable:
*/
- if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
- return 0;
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) {
+ /* assume multi socket systems are not synchronized: */
+ if (num_possible_cpus() > 1)
+ tsc_unstable = 1;
+ }
+ return tsc_unstable;
+}
+
+/*
+ * Geode_LX - the OLPC CPU has a possibly a very reliable TSC
+ */
+#ifdef CONFIG_MGEODE_LX
+/* RTSC counts during suspend */
+#define RTSC_SUSP 0x100
- /* assume multi socket systems are not synchronized: */
- return num_possible_cpus() > 1;
+static void __init check_geode_tsc_reliable(void)
+{
+ unsigned long val;
+
+ rdmsrl(MSR_GEODE_BUSCONT_CONF0, val);
+ if ((val & RTSC_SUSP))
+ clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
}
+#else
+static inline void check_geode_tsc_reliable(void) { }
+#endif
static int __init init_tsc_clocksource(void)
{
/* check blacklist */
dmi_check_system(bad_tsc_dmi_table);
- if (unsynchronized_tsc()) /* mark unstable if unsynced */
- mark_tsc_unstable();
+ unsynchronized_tsc();
+ check_geode_tsc_reliable();
current_tsc_khz = tsc_khz;
clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
clocksource_tsc.shift);
/* lower the rating if we already know its unstable: */
- if (check_tsc_unstable())
+ if (check_tsc_unstable()) {
clocksource_tsc.rating = 0;
-
- init_timer(&verify_tsc_freq_timer);
- verify_tsc_freq_timer.function = verify_tsc_freq;
- verify_tsc_freq_timer.expires =
- jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL);
- add_timer(&verify_tsc_freq_timer);
+ clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
+ }
return clocksource_register(&clocksource_tsc);
}
projects / linux-2.6 / blobdiff