drivers/firmware: const-ify DMI API and internals

[linux-2.6-omap-h63xx.git] / arch / i386 / kernel / tsc.c

diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index f64b81f3033bcba88ff47d268e8819b93d938e47..3ed0ae8c918ddfd95da7fa452157c80f2a84e1b0 100644 (file)
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -4,6 +4,7 @@
  * See comments there for proper credits.
  */
 
+#include <linux/sched.h>
 #include <linux/clocksource.h>
 #include <linux/workqueue.h>
 #include <linux/cpufreq.h>
@@ -26,6 +27,7 @@ static int tsc_enabled;
  * an extra value to store the TSC freq
  */
 unsigned int tsc_khz;
+EXPORT_SYMBOL_GPL(tsc_khz);
 
 int tsc_disable;
 
@@ -57,10 +59,11 @@ __setup("notsc", tsc_setup);
  */
 static int tsc_unstable;
 
-static inline int check_tsc_unstable(void)
+int check_tsc_unstable(void)
 {
        return tsc_unstable;
 }
+EXPORT_SYMBOL_GPL(check_tsc_unstable);
 
 /* Accellerators for sched_clock()
  * convert from cycles(64bits) => nanoseconds (64bits)
@@ -83,7 +86,7 @@ static inline int check_tsc_unstable(void)
  *
  *                     -johnstul@us.ibm.com "math is hard, lets go shopping!"
  */
-static unsigned long cyc2ns_scale __read_mostly;
+unsigned long cyc2ns_scale __read_mostly;
 
 #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
 
@@ -92,32 +95,44 @@ static inline void set_cyc2ns_scale(unsigned long cpu_khz)
        cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
 }
 
-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
-{
-       return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
-}
-
 /*
  * Scheduler clock - returns current time in nanosec units.
  */
-unsigned long long sched_clock(void)
+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_enabled))
+       if (unlikely(!tsc_enabled && !tsc_unstable))
                /* No locking but a rare wrong value is not a big deal: */
                return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
 
        /* read the Time Stamp Counter: */
-       get_scheduled_cycles(this_offset);
+       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;
@@ -290,7 +305,7 @@ void mark_tsc_unstable(char *reason)
 }
 EXPORT_SYMBOL_GPL(mark_tsc_unstable);
 
-static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
+static int __init dmi_mark_tsc_unstable(const struct dmi_system_id *d)
 {
        printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
                       d->ident);