#include <asm/delay.h>
#include <asm/tsc.h>
#include <asm/io.h>
+#include <asm/timer.h>
#include "mach_timer.h"
+static int tsc_enabled;
+
/*
* On some systems the TSC frequency does not
* change with the cpu frequency. So we need
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;
/*
- * in the NUMA case we dont use the TSC as they are not
- * synchronized across all CPUs.
+ * Fall back to jiffies if there's no TSC available:
*/
-#ifndef CONFIG_NUMA
- if (!cpu_khz || check_tsc_unstable())
-#endif
- /* no locking but a rare wrong value is not a big deal */
+ if (unlikely(!tsc_enabled))
+ /* 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);
+ 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;
EXPORT_SYMBOL(recalibrate_cpu_khz);
-void __init tsc_init(void)
-{
- if (!cpu_has_tsc || tsc_disable)
- return;
-
- cpu_khz = calculate_cpu_khz();
- tsc_khz = cpu_khz;
-
- if (!cpu_khz)
- return;
-
- printk("Detected %lu.%03lu MHz processor.\n",
- (unsigned long)cpu_khz / 1000,
- (unsigned long)cpu_khz % 1000);
-
- set_cyc2ns_scale(cpu_khz);
- use_tsc_delay();
-}
-
#ifdef CONFIG_CPU_FREQ
-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 *work)
-{
- unsigned int cpu;
-
- for_each_online_cpu(cpu)
- cpufreq_get(cpu);
-
- cpufreq_delayed_issched = 0;
-}
-
-/*
- * if we notice cpufreq oddness, 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 "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.
{
struct cpufreq_freqs *freq = data;
- if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
- write_seqlock_irq(&xtime_lock);
-
if (!ref_freq) {
if (!freq->old){
ref_freq = freq->new;
- goto end;
+ return 0;
}
ref_freq = freq->old;
loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
* TSC based sched_clock turns
* to junk w/ cpufreq
*/
- mark_tsc_unstable();
+ mark_tsc_unstable("cpufreq changes");
}
}
}
-end:
- if (val != CPUFREQ_RESUMECHANGE && val != CPUFREQ_SUSPENDCHANGE)
- write_sequnlock_irq(&xtime_lock);
return 0;
}
static int __init cpufreq_tsc(void)
{
- int ret;
-
- INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get);
- ret = cpufreq_register_notifier(&time_cpufreq_notifier_block,
- CPUFREQ_TRANSITION_NOTIFIER);
- if (!ret)
- cpufreq_init = 1;
-
- return ret;
+ return cpufreq_register_notifier(&time_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
}
-
core_initcall(cpufreq_tsc);
#endif
/* 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(char *reason)
{
- int change = 0;
-
- /* check to see if we should switch to the safe clocksource: */
- if (clocksource_tsc.rating != 0 && check_tsc_unstable()) {
- clocksource_tsc.rating = 0;
- clocksource_reselect();
- 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;
+ tsc_enabled = 0;
+ printk("Marking TSC unstable due to: %s.\n", reason);
+ /* 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.
*/
-static __init int unsynchronized_tsc(void)
+__cpuinit int unsynchronized_tsc(void)
{
+ if (!cpu_has_tsc || tsc_unstable)
+ return 1;
/*
* 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
+
+static void __init check_geode_tsc_reliable(void)
+{
+ unsigned long val;
- /* assume multi socket systems are not synchronized: */
- return num_possible_cpus() > 1;
+ 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)
+
+void __init tsc_init(void)
{
+ if (!cpu_has_tsc || tsc_disable)
+ goto out_no_tsc;
+
+ cpu_khz = calculate_cpu_khz();
+ tsc_khz = cpu_khz;
+
+ if (!cpu_khz)
+ goto out_no_tsc;
+
+ printk("Detected %lu.%03lu MHz processor.\n",
+ (unsigned long)cpu_khz / 1000,
+ (unsigned long)cpu_khz % 1000);
- if (cpu_has_tsc && tsc_khz && !tsc_disable) {
- /* check blacklist */
- dmi_check_system(bad_tsc_dmi_table);
+ set_cyc2ns_scale(cpu_khz);
+ use_tsc_delay();
+
+ /* Check and install the TSC clocksource */
+ dmi_check_system(bad_tsc_dmi_table);
- if (unsynchronized_tsc()) /* mark unstable if unsynced */
- mark_tsc_unstable();
- current_tsc_khz = tsc_khz;
- clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ 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())
- clocksource_tsc.rating = 0;
+ /* lower the rating if we already know its unstable: */
+ if (check_tsc_unstable()) {
+ clocksource_tsc.rating = 0;
+ clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS;
+ } else
+ tsc_enabled = 1;
- 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_register(&clocksource_tsc);
- return clocksource_register(&clocksource_tsc);
- }
+ return;
- return 0;
+out_no_tsc:
+ /*
+ * Set the tsc_disable flag if there's no TSC support, this
+ * makes it a fast flag for the kernel to see whether it
+ * should be using the TSC.
+ */
+ tsc_disable = 1;
}
-
-module_init(init_tsc_clocksource);
projects / linux-drm-fsl-dcu.git / blobdiff