1 /* 2 * x86 TSC related functions 3 */ 4 #ifndef _ASM_X86_TSC_H 5 #define _ASM_X86_TSC_H 6 7 #include <asm/processor.h> 8 9 #define NS_SCALE 10 /* 2^10, carefully chosen */ 10 #define US_SCALE 32 /* 2^32, arbitralrily chosen */ 11 12 /* 13 * Standard way to access the cycle counter. 14 */ 15 typedef unsigned long long cycles_t; 16 17 extern unsigned int cpu_khz; 18 extern unsigned int tsc_khz; 19 20 extern void disable_TSC(void); 21 22 static inline cycles_t get_cycles(void) 23 { 24 #ifndef CONFIG_X86_TSC 25 if (!cpu_has_tsc) 26 return 0; 27 #endif 28 29 return rdtsc(); 30 } 31 32 extern void tsc_init(void); 33 extern void mark_tsc_unstable(char *reason); 34 extern int unsynchronized_tsc(void); 35 extern int check_tsc_unstable(void); 36 extern int check_tsc_disabled(void); 37 extern unsigned long native_calibrate_tsc(void); 38 extern unsigned long long native_sched_clock_from_tsc(u64 tsc); 39 40 extern int tsc_clocksource_reliable; 41 42 /* 43 * Boot-time check whether the TSCs are synchronized across 44 * all CPUs/cores: 45 */ 46 extern void check_tsc_sync_source(int cpu); 47 extern void check_tsc_sync_target(void); 48 49 extern int notsc_setup(char *); 50 extern void tsc_save_sched_clock_state(void); 51 extern void tsc_restore_sched_clock_state(void); 52 53 /* MSR based TSC calibration for Intel Atom SoC platforms */ 54 unsigned long try_msr_calibrate_tsc(void); 55 56 #endif /* _ASM_X86_TSC_H */ 57