2 * x86 TSC related functions
7 #include <asm/processor.h>
9 #define NS_SCALE 10 /* 2^10, carefully chosen */
10 #define US_SCALE 32 /* 2^32, arbitralrily chosen */
13 * Standard way to access the cycle counter.
15 typedef unsigned long long cycles_t;
17 extern unsigned int cpu_khz;
18 extern unsigned int tsc_khz;
19 /* flag for disabling the tsc */
20 extern int tsc_disable;
22 extern void disable_TSC(void);
24 static inline cycles_t get_cycles(void)
26 unsigned long long ret = 0;
28 #ifndef CONFIG_X86_TSC
33 #if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
39 static inline cycles_t vget_cycles(void)
42 * We only do VDSOs on TSC capable CPUs, so this shouldnt
43 * access boot_cpu_data (which is not VDSO-safe):
45 #ifndef CONFIG_X86_TSC
49 return (cycles_t) native_read_tsc();
52 extern void tsc_init(void);
53 extern void mark_tsc_unstable(char *reason);
54 extern int unsynchronized_tsc(void);
55 extern void init_tsc_clocksource(void);
56 int check_tsc_unstable(void);
59 * Boot-time check whether the TSCs are synchronized across
62 extern void check_tsc_sync_source(int cpu);
63 extern void check_tsc_sync_target(void);
65 extern void tsc_calibrate(void);
66 extern int notsc_setup(char *);