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 (!boot_cpu_has(X86_FEATURE_TSC)) 26 return 0; 27 #endif 28 29 return rdtsc(); 30 } 31 32 extern struct system_counterval_t convert_art_to_tsc(cycle_t art); 33 34 extern void tsc_init(void); 35 extern void mark_tsc_unstable(char *reason); 36 extern int unsynchronized_tsc(void); 37 extern int check_tsc_unstable(void); 38 extern unsigned long native_calibrate_cpu(void); 39 extern unsigned long native_calibrate_tsc(void); 40 extern unsigned long long native_sched_clock_from_tsc(u64 tsc); 41 42 extern int tsc_clocksource_reliable; 43 44 /* 45 * Boot-time check whether the TSCs are synchronized across 46 * all CPUs/cores: 47 */ 48 extern void check_tsc_sync_source(int cpu); 49 extern void check_tsc_sync_target(void); 50 51 extern int notsc_setup(char *); 52 extern void tsc_save_sched_clock_state(void); 53 extern void tsc_restore_sched_clock_state(void); 54 55 unsigned long cpu_khz_from_msr(void); 56 57 #endif /* _ASM_X86_TSC_H */ 58