1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * x86 TSC related functions
4 */
5#ifndef _ASM_X86_TSC_H
6#define _ASM_X86_TSC_H
7
8#include <asm/processor.h>
9
10#define NS_SCALE 10 /* 2^10, carefully chosen */
11#define US_SCALE 32 /* 2^32, arbitralrily chosen */
12
13/*
14 * Standard way to access the cycle counter.
15 */
16typedef unsigned long long cycles_t;
17
18extern unsigned int cpu_khz;
19extern unsigned int tsc_khz;
20
21extern void disable_TSC(void);
22
23static inline cycles_t get_cycles(void)
24{
25#ifndef CONFIG_X86_TSC
26 if (!boot_cpu_has(X86_FEATURE_TSC))
27 return 0;
28#endif
29
30 return rdtsc();
31}
32
33extern struct system_counterval_t convert_art_to_tsc(u64 art);
34extern struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns);
35
36extern void tsc_early_init(void);
37extern void tsc_init(void);
38extern unsigned long calibrate_delay_is_known(void);
39extern void mark_tsc_unstable(char *reason);
40extern int unsynchronized_tsc(void);
41extern int check_tsc_unstable(void);
42extern void mark_tsc_async_resets(char *reason);
43extern unsigned long native_calibrate_cpu_early(void);
44extern unsigned long native_calibrate_tsc(void);
45extern unsigned long long native_sched_clock_from_tsc(u64 tsc);
46
47extern int tsc_clocksource_reliable;
48#ifdef CONFIG_X86_TSC
49extern bool tsc_async_resets;
50#else
51# define tsc_async_resets false
52#endif
53
54/*
55 * Boot-time check whether the TSCs are synchronized across
56 * all CPUs/cores:
57 */
58#ifdef CONFIG_X86_TSC
59extern bool tsc_store_and_check_tsc_adjust(bool bootcpu);
60extern void tsc_verify_tsc_adjust(bool resume);
61extern void check_tsc_sync_source(int cpu);
62extern void check_tsc_sync_target(void);
63#else
64static inline bool tsc_store_and_check_tsc_adjust(bool bootcpu) { return false; }
65static inline void tsc_verify_tsc_adjust(bool resume) { }
66static inline void check_tsc_sync_source(int cpu) { }
67static inline void check_tsc_sync_target(void) { }
68#endif
69
70extern int notsc_setup(char *);
71extern void tsc_save_sched_clock_state(void);
72extern void tsc_restore_sched_clock_state(void);
73
74unsigned long cpu_khz_from_msr(void);
75
76#endif /* _ASM_X86_TSC_H */
77