1 /* SPDX-License-Identifier: GPL-2.0 */
3 * x86 TSC related functions
8 #include <asm/processor.h>
9 #include <asm/cpufeature.h>
11 #define NS_SCALE 10 /* 2^10, carefully chosen */
12 #define US_SCALE 32 /* 2^32, arbitralrily chosen */
15 * Standard way to access the cycle counter.
17 typedef unsigned long long cycles_t;
19 extern unsigned int cpu_khz;
20 extern unsigned int tsc_khz;
22 extern void disable_TSC(void);
24 static inline cycles_t get_cycles(void)
26 #ifndef CONFIG_X86_TSC
27 if (!boot_cpu_has(X86_FEATURE_TSC))
34 extern struct system_counterval_t convert_art_to_tsc(u64 art);
35 extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
37 extern void tsc_early_init(void);
38 extern void tsc_init(void);
39 extern unsigned long calibrate_delay_is_known(void);
40 extern void mark_tsc_unstable(char *reason);
41 extern int unsynchronized_tsc(void);
42 extern int check_tsc_unstable(void);
43 extern void mark_tsc_async_resets(char *reason);
44 extern unsigned long native_calibrate_cpu_early(void);
45 extern unsigned long native_calibrate_tsc(void);
46 extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
48 extern int tsc_clocksource_reliable;
50 extern bool tsc_async_resets;
52 # define tsc_async_resets false
56 * Boot-time check whether the TSCs are synchronized across
60 extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
61 extern void tsc_verify_tsc_adjust(bool resume);
62 extern void check_tsc_sync_source(int cpu);
63 extern void check_tsc_sync_target(void);
65 static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
66 static inline void tsc_verify_tsc_adjust(bool resume) { }
67 static inline void check_tsc_sync_source(int cpu) { }
68 static inline void check_tsc_sync_target(void) { }
71 extern int notsc_setup(char *);
72 extern void tsc_save_sched_clock_state(void);
73 extern void tsc_restore_sched_clock_state(void);
75 unsigned long cpu_khz_from_msr(void);
77 #endif /* _ASM_X86_TSC_H */